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Solutions

SECTION - A

Objective Type Questions

(How to Analyse Chemical Composition? Primary and Secondary Metabolites, Carbohydrates)

1. Which of the following is not strictly a biomacromolecule?

(1) Proteins (2) Lipids (3) Polysaccharides (4) Nucleic acid

Sol. Answer (2)

Because the molecular weight of lipids does not exceed 800 Da but they come under the acid insoluble fraction.

2. A secondary metabolite that acts as a toxin is

(1) Carotenoids (2) Curcumin (3) Abrin (4) Monoterpenes

Sol. Answer (3)

Carotenoid – Pigment

Curcumin – Drug

Monoterpenes – Terpenoids

3. A secondary metabolite that is alkaloid in nature is

(1) Codeine (2) Anthocyanin (3) Gum (4) Abrin

Sol. Answer (1)

Anthocyanin – Pigment

Gum – Polymeric substance

Abrin – Toxin

4. Peptidoglycan present in bacterial cell envelope is

(1) Made up of cellulose (2) A heteropolymer (3) An oligosaccharide (4) A homopolymer

Sol. Answer (2)

Peptidoglycan is a heteropolysaccharide made up of two alternate amino sugar molecules i.e., N-acetylglucosamines and N-acetyl muramic acid.

(Proteins, Lipids)

5. The most abundant protein in animal world is

(1) Chitin (2) Collagen (3) Peptidoglycan (4) Hyaluronic acid

Chapter 2

Biomolecules

20 Biomolecules Solutions of Assignment


Sol. Answer (2)

Because chitin, peptidoglycan and hyaluronic acid, are polysaccharide, not protein.

6. The amino acids in a protein are held together by

(1) Glycosidic bond (2) Phosphodiester bond (3) Peptide bond (4) Hydrogen bond

Sol. Answer (3)

Glycosidic bond : Formed between the two monosaccharides (sugar molecule).

Phosphodiester bond : This bond is formed in nucleic acid i.e. DNA or RNA, between the phosphate andhydroxyl group of sugar.

7. A protein which exhibits β pleated structure is

(1) Fibroin (2) Haemoglobin (3) Enzyme (4) α-Keratin

Sol. Answer (1)

Haemoglobin → Quaternary structure

Enzymes → Tertiary structure

α-Keratin → Secondary structure

8. An example of protein with quaternary structure is

(1) Myoglobin (2) Haemoglobin (3) Keratin (4) All of these

Sol. Answer (2)

Myoglobin : Tertiary structure

Keratin : Secondary structure

9. Lecithin is a

(1) Type of wax (2) Phospholipid (3) Oil (4) Simple fatty acid

Sol. Answer (2)

Because lecithin made up of a molecule of glycerol, a phosphate group, 2 fatty acid molecules, choline(N-containing alcohol molecule)

O

R2

C O CH

CH2

CH2

O

O

C R1

O P

O

OH

O CH2

CH2

N

CH3

CH3

CH3

Lecithin

10. Lipids that insulate the nerve fibre are

(1) Lecithin (2) Cholesterol (3) Suberin (4) Glycolipids

Sol. Answer (4)

The glycolipids are present in myelin sheath of nerve fibres.

11. The primary precursor for the production of cholesterol in our body is

(1) Acetic acid (2) Citric acid (3) Ethyl alcohol (4) Methanol

Sol. Answer (1)

In biosynthetic pathway or anabolic pathway, the acetic acid is converted into cholesterol in liver.

21Solutions of Assignment Biomolecules


(Nucleic Acid)

12. The pentose sugar present in RNA is

(1) Galactose (2) Sucrose (3) Ribose (4) Fructose

Sol. Answer (3)

Ribose is a monosaccharide sugar present in RNA.

Deoxyribose is a derived monosaccharide sugar present in DNA.

13. Nucleoside is

(1) Sugar + Nitrogenous base (2) Sugar + Phosphate

(3) Nitrogenous base + Phosphate (4) Purine + Pyrimidine

Sol. Answer (1)

Nucleoside = Sugar + Nitrogenous base

Nucleotide = Sugar + Nitrogenous base + Phosphate

14. In B-DNA, one full turn of the helical strand contains

(1) 11 base pairs (2) 8 base pairs (3) 10 base pairs (4) 9 base pairs

Sol. Answer (3)

A form → 11 base pairs

B form → 10 base pairs

C form → 9 base pairs

D form → 8 base pairs

15. In a DNA molecule adenine of one strand base pair with ____ on the other strand

(1) Guanine (2) Thymine (3) Cytosine (4) Both (1) & (3)

Sol. Answer (2)

In DNA, A T , C G

16. In B-DNA, the rise per base pair would be

(1) 4.3 Å (2) 2.4 Å (3) 3.4 Å (4) 4.2 Å

Sol. Answer (3)

In B-DNA, the rise per base pair would be 3.4 Å.

17. The nitrogenous bases of the two strands of DNA are joined by

(1) Phosphodiester bond (2) Hydrogen bond (3) Glycosidic bond (4) Peptide bond

Sol. Answer (2)

Hydrogen bond : The bond formed between two polynucleotide strands of DNA.

Glycosidic bond : Formed between the two monosaccharides (sugar).

Peptide bond : Formed between 2 amino acids.

Phosphodiester bond : Bond formed in nucleic acid i.e. DNA or DNA, between the phosphate and hydroxylgroup of sugar.

18. The genetic material of Tobacco mosaic virus is

(1) RNA (2) DNA (3) Protein (4) NADPH

Sol. Answer (1)

The genetic material of TMV is ssRNA.



19. The double helix model of DNA was proposed by

(1) Berzelius (2) Watson and Crick (3) Griffith (4) Robert Brown

Sol. Answer (2)

The double helix model of DNA was proposed by Watson and Crick.

20. In the 5′ end of a DNA molecule

(1) The fifth carbon of pyrimidine base is free (2) The fifth carbon of purine base is free

(3) The fifth carbon of pentose sugar is free (4) Both (1) & (3)

Sol. Answer (3)

One end of the strand is called 5′ end where the fifth carbon of the pentose sugar is free and the other iscalled 3'end where the third carbon of pentose sugar is free.

21. The pitch of the B-DNA is

(1) 36 Å (2) 3.4 Å (3) 34 Å (4) 3.6 Å

Sol. Answer (3)

In B-DNA, one turn of helical strand has 10 nucleotides.

The base pairs of DNA are stacked 3.4 Å part.

∴ Pitch of the DNA = 3.4 Å × 10 = 34 Å

22. In DNA, uracil is replaced by

(1) Thymine (2) Thiamine (3) Cytosine (4) Adenine

Sol. Answer (1)

In DNA, thymine is present.

In RNA, uracil is present.

(Amino Acid and Dynamic State of Body Constituents–Concept of Metabolism)

23. In glycine the R group is replaced by

(1) A methyl group (2) Hydroxy methyl (3) A carboxylic group (4) A hydrogen

Sol. Answer (4)

Glycine is a simplest amino acid in which R-group is replaced by hydrogen.

24. Zwitterions are ionized species of

(1) Acidic amino acids (2) Basic amino acids

(3) Neutral amino acids (4) All of these

Sol. Answer (4)

Since amino acid can carry both +ve and –ve charges simultaneously, hence they are termed as Zwitterions.

25. Non-essential amino acids

(1) Must be obtained from food (2) Are synthesized in our body

(3) Are not needed in our diet (4) Both (2) & (3)

Sol. Answer (4)

Because non-essential amino acid are synthesised in our body, so there is no need to take it in our diet.

26. Metabolic flux is regulated by

(1) Enzymes (2) Sugars (3) Phospholipids (4) Sterols

Sol. Answer (1)

Metabolic flux is the rate of turn over of molecules through a metabolic pathway.



(The Living State, Enzymes)

27. Proteins which catalyse biochemical reactions in the living world are known as

(1) Enzymes (2) Hormones (3) Antibodies (4) Receptor

Sol. Answer (1)

Because almost all enzymes are protein which catalyse the biochemical reaction.

Hormones can be steroid and amino-acid derivative also.

Antibodies are glycoprotein.

Receptors are associated with sensory reception.

28. Ribozymes are _______ that behave like enzymes

(1) Proteins

(2) Ribonucleic acids

(3) Oligosaccharide

(4) Simple lipids

Sol. Answer (2)

Because ribozymes are the RNA which act as an enzyme.

29. The most abundant enzyme in the biosphere is

(1) Collagen (2) RuBisCO (3) Trypsin (4) Insulin

Sol. Answer (2)

Ribulose bisphosphate carboxylase-oxygenase (RuBisCO) is the most abundant protein in the whole of thebiosphere.

30. What is the fate of pyruvic acid under anaerobic conditions in our body?

(1) It gets converted into methyl alcohol

(2) It gets converted into acetyl CoA

(3) It gets converted into lactic acid

(4) It gets converted into glycogen

Sol. Answer (3)

Under anaerobic condition, the glucose is converted into lactic acid in muscle.

31. Organic compounds that are tightly bound to apoenzyme is

(1) Prosthetic group (2) Apoenzyme (3) Metal ions (4) Co-enzymes

Sol. Answer (1)

Enzyme (Holoenzyme)

Protein part(Apozyme)

Non-protein part(Cofactor)

InorganicOrganic compound

Loosely bound(Co-enzyme)

Tightly bound(Prosthetic group)

It includes metal ions

, Zn , Mg etc.i.e.2+ 2+

,



32. Bacterial pathogen can be controlled by

(1) p-amino benzoic acid (2) Malonate (3) Sulphanilamide (4) All of these

Sol. Answer (3)

Sulpha drugs are derivatives of sulphanilamide, which inhibit the synthesis of folic acid in bacteria by competingwith p-amino benzoic acid (PABA) required for the synthesis of folic acid by folic acid synthetase.

33. Non-protein part of enzyme is known as

(1) Apoenzyme (2) Cofactor (3) Inorganic catalyst (4) Active site

Sol. Answer (2)

Enzyme (Holoenzyme)

Protein part(Apozyme)

Non-protein part(Cofactor)

InorganicOrganic compound

Loosely bound(Co-enzyme)



, Zn , Mg etc.i.e.2+ 2+

SECTION - B


(How to Analyse Chemical Composition? Primary and Secondary Metabolites, Carbohydrates)

1. In maltose glycosidic bond is formed between

(1) Carbon 1 of one glucose molecule and carbon 4 of second glucose molecule




Sol. Answer (1)

H

OH

H

CH OH2

H

OH

H

H

OH

O

1

H

O

H

CH OH2

H

OH

H

H

OH

O

4

OH

2. The given structure represents a monosaccharide known as

O

OH OH

HOCH2

OH OH

(1) Ribose (2) Glucose (3) Fructose (4) Raffinose

Sol. Answer (1)

Ribose is a pentose sugar.



3. Chitin present in the exoskeletons of arthropods is

(1) Protein (2) Polysaccharide

(3) Lipid (4) Derived monosaccharide

Sol. Answer (2)

Because chitin is a polymer of nitrogen containing glucose derivative known as N-acetyl glucosamine.

4. One of the following is correct sequence of carbohydrates in the order of increasing complexity of chemical

structure

(1) Sucrose, starch, oligosaccharide, maltose, triose (2) Triose, maltose, sucrose, oligosaccharide, starch

(3) Triose, glucose, maltose, oligosaccharide, starch (4) Oligosaccharide, triose, starch, sucrose, maltose

Sol. Answer (3)

Triose – 3 C containing molecule

Glucose – Monosaccharide (6 C)

Maltose – Disaccharide (2 Monosaccharide units)

Oligosaccharide – (2–10) Monosaccharide units

Starch – Polysaccharides

5. Glucose is stored as glycogen in

(1) Pancreas (2) Bone (3) Kidney (4) Liver

Sol. Answer (4)

Because liver is a gland where glucose get converted into glycogen.

6. A cellulose molecule is formed by the polymerisation of glucose. The number of glucose molecules present

in a cellulose is

(1) 600 (2) 6000 (3) 60,000 (4) 60

Sol. Answer (2)

A cellulose molecule is formed by polymerisation of 6000 molecules of β glucose.

(Proteins, Lipids and Nucleic Acids)

7. The structure of protein which gives a three dimensional view is

(1) Primary structure (2) α-helix

(3) β-pleated sheet (4) Tertiary structure

Sol. Answer (4)

Tertiary structure of protein gives a three dimensional view.

8. The product of the given reaction would be a

CH OH2

CH OH2

CHOH +

HOOC–R1

HOOC–R3

HOOC–R2

Glycerol Fatty acid

(1) Monoglyceride (2) Diglyceride (3) Triglyceride (4) Both (1) & (3)



Sol. Answer (3)

Because given structure has three fatty acids.

9. The given fatty acid is known as CH3(CH

2)7 CH = CH (CH

2)7 COOH

(1) Palmitic acid (2) Oleic acid (3) Stearic acid (4) Arachidonic acid

Sol. Answer (2)

(CH3)2(CH

2)7CH = CH(CH

2)7COOH – Oleic acid

CH3(CH

2)14

COOH – Palmitic acid

CH3(CH

2)16

COOH – Stearic acid

Arachidonic acid : CH3(CH

2)4CH = CHCH

2CH = CHCH

2CH = CHCH

2CH = CH(CH

2)3COOH

(20 C)

10. Nucleic acids exhibit

(1) Secondary structure (2) Tertiary structure (3) Quaternary structure (4) Both (2) & (3)

Sol. Answer (1)

Because nucleic acid (DNA) has double helical structure and it comes under secondary structure.

11. The backbone of a DNA molecule is made up of

(1) Adenine and guanine (2) Sugar-phosphate-sugar chain

(3) Cytosine and thymine (4) All of these

Sol. Answer (2)

Backbone of a DNA molecule is made up of Sugar – Phosphate – Sugar chain

SS

SS

P P

A T

G C

T A

3'

5' 3'

5'

SS

P P

P

P

P = PhosphateS = SugarA = AdenineT = ThymineG = GuanineC = Cytosine

12. If the sequence of bases in one of the DNA strand is A G G A G A A, then the sequence of bases in the othercomplementary strand of DNA would be

(1) C C T T C T T (2) T C T C T C C (3) T C C T C T T (4) C C T C T C T

Sol. Answer (3)

Because A = T, G ≡ C

13. RNA is a polymer of

(1) Ribonucleotides (2) Deoxyribonucleotides

(3) Deoxyribonucleosides (4) Ribonucleosides

Sol. Answer (1)

It is made up of ribose sugar, phosphate and nitrogenous bases (A, U, G, C).



14. t-RNA constitutes about

(1) 70-80% of the total RNA (2) 15% of the total RNA

(3) 5% of the total RNA (4) 1-3% of the total RNA

Sol. Answer (2)

r-RNA → 70 – 80% of total RNA

t-RNA → 15% of total RNA

m-RNA → 2–5% of total RNA

15. In DNA, cytosine pairs with

(1) Guanine (2) Thymine (3) Adenine (4) Uracil

Sol. Answer (1)

A = T (2 hydrogen bonds between adenine and thymine)

G ≡ C (3 hydrogen bonds between cytosine and guanine)

(Amino Acid and Dynamic State of Body Constituents–Concept of Metabolism)

16. The given amino acid is _______ in nature.

H N–C–H2

COOH

CH .COOH2

(1) Acidic (2) Basic (3) Neutral (4) Aromatic

Sol. Answer (1)

Because given structure has an extra carboxylic group.

17. Which of the following are basic amino acids?

(1) Glycine and Alanine (2) Lysine and Arginine

(3) Glutamic acid and Aspartic acid (4) Histidine and Proline

Sol. Answer (2)

Lysine and Arginine → Basic amino acid → +ve charged

Glutamic acid and Aspartic acid → Acidic amino acid → –ve charge

18. Which of the following aminoacids is involved in the formation of Heme?

(1) Tryptophan (2) Tyrosine (3) Glycine (4) Histidine

Sol. Answer (3)

Because amino-acid glycine provides nitrogen and carbon atoms for the synthesis of heme.

19. Which one of the following is alcoholic amino acid pair?

(1) Tyrosine and serine (2) Threonine and serine

(3) Phenylalanine and tyrosine (4) Tryptophan and phenylalanine

Sol. Answer (2)

Because these two amino acids contain alcohol group.



20. Lysine is an essential amino acid because

(1) It is very rare

(2) It has a high nutritive value

(3) It is an important constituent of all proteins

(4) It is not formed in the body and has to be provided through diet

Sol. Answer (4)

Essential amino acids are not synthesised in body.

21. In which of the following energy is released?

(1) Conversion of glucose into pyruvate (2) Formation of proteins from amino acids

(3) Conversion of glucose into lactic acid (4) Both (1) & (3)

Sol. Answer (4)

Anaerobic combustion of glucose releases energy in the form of ATP.

22. Adenosine Triphosphate (ATP) liberates high energy by the breakdown of

(1) Glycosidic bond (2) Hydrogen bond

(3) Phosphate bond (4) Both (1) & (3)

Sol. Answer (3)

ATP ⎯→ ADP + iP (inorganic phosphate)

(The Living State, Enzymes)

23. Which of the following statements is correct?

(1) Biocatalysts accelerate the rate of a given metabolic reaction

(2) Biocatalysts are generally protein

(3) Enzyme catalyst differ from inorganic catalyst

(4) All of these

Sol. Answer (4)

24. Which of the following statements is incorrect w.r.t. inorganic catalysts?

(1) They do not occur in living cells (2) They are not specific for any reaction

(3) They get damaged at high temperature (4) They work efficiently at high pressure

Sol. Answer (3)

Inorganic catalyst work efficiently at high temperature and pressure, but enzyme get damaged at high

temperature (i.e. above 40ºC) except thermophillic enzyme.

25. Enzymes catalyse biochemical reactions by

(1) Lowering the activation energy

(2) Increasing the activation energy

(3) Establishing stable bonds with substrate

(4) Increasing temperature

Sol. Answer (1)

Enzyme lowers the activation energy and thus increases the rate of reaction.



26. Read the following :

(a) Low temperature preserves the enzyme

(b) Enzyme activity increases above optimum temperature

(c) Enzyme gets denatured at high temperature

(d) Competitive inhibitor competes with the product formed

Which of the following statement are true?

(1) (a) & (c) (2) (b) & (d) (3) (c) & (d) (4) (a) & (b)

Sol. Answer (1)

(b) Statement is wrong because enzyme activity decreases above optimum temperature.

(d) Statement is wrong because competitive inhibitor completes with substrate for active site, not with product

formed.

27. Enzymes catalysing the breakdown of larger molecules into smaller molecules are

(1) Hydrolases (2) Isomerases (3) Ligase (4) Both (1) & (3)

Sol. Answer (1)

Because, hydrolases are the enzyme which catalyse the breakdown of larger molecules into smaller molecules

with the addition of water.

Isomerases : They are the enzymes which catalyse the rearrangement of molecular structure to form isomers.

Ligases : They help in joining C – O, C – S, C – N etc. bonds by using energy of ATP.

28. Michaelis constant (Km

) value of enzyme is substrate concentration at which velocity of reaction is

(1) Vmax

(2) One third Vmax

(3) Half Vmax

(4) One fifth Vmax

Sol. Answer (3)

Vmax

Km

[s]

Vmax

2

Velocityof reaction

29. _______ catalyses covalent bonding of two substrates.

(1) Invertase

(2) Amylase

(3) Glutamate pyruvate transaminase

(4) PEP carboxylase

Sol. Answer (4)

Because this is a ligase enzyme.



30. The enzyme that catalyses the conversion of glucose-6-phosphate into fructose-6-phosphate is

(1) A ligase (2) An isomerase

(3) A lyase (4) A hydrolase

Sol. Answer (2)

Glucose-6-phosphate isomerase

��⇀↽�� fructose-6-phosphate

31. Study the following statements :

(a) The substrate binds to the active site of the enzyme

(b) Enzymes isolated from thermophilic organisms get denatured at 50°C

(c) The active site of enzyme breaks the chemical bonds of the product

(d) Prosthetic groups are tightly bound to the apoenzyme

Select the option which includes all correct statements :

(1) (a) & (c) (2) (c) & (d) (3) (b) & (c) (4) (a) & (d)

Sol. Answer (4)

(b) Statement is wrong, because thermophillic enzymes don't get denatured at high temperature, they work

efficiently at high temperature (750ºC).

(c) Statement is wrong, because enzyme don't break chemical bonds of product but of substrate.

32. All enzymes are proteins, except

(1) Trypsin (2) Pepsin

(3) Steapsin (4) Ribozyme and Ribonuclease-P

Sol. Answer (4)

Because, all enzymes are proteins, except, ribozyme and ribonuclease-P, which are RNA act as enzyme.

33. Cyanide kills an animal by

(1) Killing the brain cells

(2) Competitive inhibitor of enzyme cytochrome oxidise

(3) Inhibiting cytochrome oxidase, a mitochondrial enzyme essential for cellular respiration by Non-competitive

inhibition

(4) Killing the cells of cardiac muscles

Sol. Answer (3)

Cyanide poisoining is an example of non competitive inhibition of enzyme.

34. Electron transferring enzymes belong to

(1) Transferases (2) Oxidoreductases (3) Lyases (4) Isomerases

Sol. Answer (2)

The main enzymes of electron transport chain are dehydrogenase, reductase, cytochrome oxidase, which

belongs to the oxidoreductase class of an enzyme.



SECTION - C

Previous Years Questions

1. Which of the following are not polymeric? [NEET-2017]

(1) Nucleic acids (2) Proteins (3) Polysaccharides (4) Lipids

Sol. Answer (4)

– Nucleic acids are polymers of nucleotides

– Proteins are polymers of amino acids

– Polysaccharides are polymers of monosaccharides

– Lipids are the esters of fatty acids and alcohol

2. Which one of the following statements is correct, with reference to enzymes? [NEET-2017]

(1) Apoenzyme = Holoenzyme + Coenzyme (2) Holoenzyme = Apoenzyme + Coenzyme

(3) Coenzyme = Apoenzyme + Holoenzyme (4) Holoenzyme = Coenzyme + Cofactor

Sol. Answer (2)

Holoenzyme is conjugated enzyme in which protein part is apoenzyme while non-protein is cofactor.

Coenzyme are also organic compounds but their association with apoenzyme is only transient and serve ascofactors.

3. A non-proteinaceous enzyme is [NEET(Phase-2) 2016]

(1) Lysozyme (2) Ribozyme (3) Ligase (4) Deoxyribonuclease

Sol. Answer (2)

Ribozyme is RNA acting like an enzyme or biocatalyst.

4. Which of the following is the least likely to be involved in stabilizing the three-dimensional folding of mostproteins? [NEET(Phase-2) 2016]

(1) Hydrogen bonds (2) Electrostatic interaction

(3) Hydrophobic interaction (4) Ester bonds

Sol. Answer (4)

Ester bond is formed between sugar and phosphate in a nucleotide.

5. Which of the following describes the given graph correctly? [NEET(Phase-2) 2016]

Reaction

Substrate

Pote

ntial E

nerg

y

A

B

Product

(1) Endothermic reaction with energy A in presence of enzyme and B in absence of enzyme

(2) Exothermic reaction with energy A in presence of enzyme and B in absence of enzyme

(3) Endothermic reaction with energy A in absence of enzyme and B in presence of enzyme

(4) Exothermic reaction with energy A in absence of enzyme and B in presence of enzyme

Sol. Answer (2)

Potential energy of substrate is more than the product. So it is an exothermic reaction. 'A' represents theactivation energy in the presence of enzyme while 'B' in the absence of enzyme i.e., enzyme lowers downthe activation energy.



6. A typical fat molecule is made up of [NEET-2016]

(1) Three glycerol and three fatty acid molecules

(2) Three glycerol molecules and one fatty acid molecule

(3) One glycerol and three fatty acid molecules

(4) One glycerol and one fatty acid molecule

Sol. Answer (3)

A typical fat molecule is triglyceride formed by esterification of one glycerol and three fatty acid molecules.

7. Which one of the following statements is wrong? [NEET-2016]

(1) Glycine is a sulphur containing amino acid (2) Sucrose is a disaccharide

(3) Cellulose is a polysaccharide (4) Uracil is a pyrimidine

Sol. Answer (1)

Glycine is simplest amino acid in which 'R' is replaced by H(Hydrogen).

8. Which of the following biomolecules does have a phosphodiester bond? [Re-AIPMT-2015]

(1) Nucleic acids in a nucleotide (2) Fatty acids in a diglyceride

(3) Monosaccharides in a polysaccharide (4) Amino acids in a polypeptide

Sol. Answer (1)

Phosphodiester bond is formed between two nucleotides of nucleic acid.

9. The chitinous exoskeleton of arthropods is formed by the polymerisation of [Re-AIPMT-2015]

(1) Lipoglycans (2) Keratin sulphate and chondroitin sulphate

(3) D-glucosamine (4) N-acetyl glucosamine

Sol. Answer (4)

Exoskeleton of arthropods is made up of chitin. Chitin is a polymer of N-acetyl glucosamine.

10. Which one of the following is not applicable to RNA? [Re-AIPMT-2015]

(1) Chargaff's rule

(2) Complementary base pairing

(3) 5' phosphoryl and 3' hydroxyl ends

(4) Heterocyclic nitrogenous bases

Sol. Answer (1)

Chargaff's rule is applicable only for DNA.

11. In sea urchin DNA, which is double stranded 17% of the bases were shown to be cytosine. The percentagesof the other three bases expected to be present in this DNA are [AIPMT-2015]

(1) G 8.5%, A 50%, T 24.5%

(2) G 34%, A 24.5%, T 24.5%

(3) G 17%, A 16.5%, T 32.5%

(4) G 17%, A 33%, T 33%

Sol. Answer (4)



12. Which one of the following statements is incorrect? [AIPMT-2015]

(1) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate

(2) A competitive inhibitor reacts reversibly with the enzyme to form an enzyme-inhibitor complex

(3) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme

(4) The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex

Sol. Answer (1)

13. Select the option which is not correct with respect to enzyme action: [AIPMT-2014]

(1) Substrate binds with enzyme at its active site

(2) Addition of lot of succinate does not reverse the inhibition of succinic dehydrogenase by malonate

(3) A non - competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate

(4) Malonate is a competitive inhibitor of succinic dehydrogenase

Sol. Answer (2)

Inhibition of succinic dehydrogenase by malonate is an example of competitive inhibition. This is reversiblereaction. On increasing the substrate (succinate) concentration the effect of inhibitor is removed and V

max

remain same.

14. Which one of the following is a non - reducing carbohydrate? [AIPMT-2014]

(1) Maltose (2) Sucrose (3) Lactose (4) Ribose 5-phosphate

Sol. Answer (2)

Lactose, Maltose, Ribose 5-phosphate all are reducing sugars.

15. A phosphoglyceride is always made up of: [NEET-2013]

(1) Only an unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached

(2) A saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is alsoattached

(3) A saturated or unsaturated fatty acid esterified to a phosphate group which is also attached to a glycerolmolecule

(4) Only a saturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached

Sol. Answer (2)

16. The essential chemical components of many coenzymes are: [NEET-2013]

(1) Nucleic acids (2) Carbohydrates (3) Vitamins (4) Proteins

Sol. Answer (3)

17. Transition state structure of the substrate formed during an enzymatic reaction is : [NEET-2013]

(1) Permanent but unstable (2) Transient and unstable

(3) Permanent and stable (4) Transient but stable

Sol. Answer (2)

18. Macromolecule chitin is [NEET-2013]

(1) Phosphorus containing polysaccharide (2) Sulphur containing polysaccharide

(3) Simple polysaccharide (4) Nitrogen containing polysaccharide

Sol. Answer (4)



19. Which one out of A – D given below correctly represents the structural formula of the basic amino acid?

NH

|C|CH

|CH

|C

2

2

2

OHO

H COOH

A B C D

NH

|C|CH

|OH

2

2

H COOH

CH OH

|CH

|CH

|NH

2

2

2

2

NH2

C

CH2

|CH

2

|CH

2

|CH

2

|NH

2

H COOH

[AIPMT (Prelims)-2012]

(1) A (2) B (3) C (4) D

Sol. Answer (4)

Because in 'D', it has an extra amino group, because of which it carry +ve charge which comes under basicamino acid.

20. Given below is the diagrammatic representation of one of the categories of small molecular weight organic compoundsin the living tissues. Identify the category shown and the one blank component “X” in it

OHOCH2

"X"

OH OH


Category Component

(1) Nucleotide Adenine

(2) Nucleoside Uracil

(3) Cholesterol Guanin

(4) Amino acid NH2

Sol. Answer (2)

Because the given structure doesn't have phosphate group so it is nucleoside and "X" is uracil because itconsists ribose sugar.

21. For its activity, carboxypeptidase requires [AIPMT (Mains)-2012]

(1) Copper (2) Zinc (3) Iron (4) Niacin

Sol. Answer (2)

Carboxypeptidase require Zn2+ metal ion.

22. Which one of the following biomolecules is correctly characterised? [AIPMT (Mains)-2012]

(1) Alanine amino acid – Contains an amino group and an acidic group anywhere in the molecule

(2) Lecithin – a phosphorylated glyceride found in cell membrane

(3) Palmitic acid – an unsaturated fatty acid with 18 carbon atoms

(4) Adenylic acid – adenosine with a glucose phosphate molecule

Sol. Answer (2)

Option (1) is wrong, because alanine contains an amino group and an acidic group at α-carbon in the molecule.

Option (3) is wrong, because palmitic acid is a saturated fatty acid with 16C atoms.

Option (4) is wrong, because adenylic acid is form by adding phosphate group to adenosine.



23. The curve given below show enzymatic activity with relation to three conditions (pH, temperature and substrateconcentration)

y-axis

x-axis

What do the two axes (x and y) represent? [AIPMT (Prelims)-2011]

x-axis y-axis

(1) Enzymatic activity Temperature

(2) Enzymatic activity pH

(3) Temperature Enzyme activity

(4) Substrate concentration Enzymatic activity

Sol. Answer (3)

x

y

pH or Temperature

Enzymatic activity

24. Which one of the following structural formulae of two organic compound is correctly identified along with itsrelated function

R —C—O—CH2

CH —O—C—R2

CH —O—P—O—CH —CH2 22

O

O

O

OH N

CH3CH

3

CH3

A

+ NH

N

NH2

N

N

B[AIPMT (Prelims)-2011]

(1) A : Lecithin – a component of cell membrane

(2) B : Adenine – a nucleotide that makes up nucleic acids

(3) A : Triglyceride – major source of energy

(4) B : Uracil – a component of DNA

Sol. Answer (1)

Given structure 'A' is Leathin and 'B' is Adenine.

25. The figure given below shows the conversion of a substrate into product by an enzyme. In which one of the

four options (1–4) the components of reaction labelled as A, B, C and D are identified correctly?

B Substrate

Product

Progress of Reaction

C

D

A

[AIPMT (Mains)-2010]



A B C D

(1) Potential energy Transition state Activation energy with

enzyme

Activation energy

without enzyme

(2) Transit ion state Potential energy Activation energy

without enzyme

Activation energy with

enzyme

(3) Activation energy without enzyme

Transition state Activation energy with enzyme

Potential energy

(4) Activation energy with enzyme

Transition state Activation energy without enzyme

Potential energy

Sol. Answer (2)

26. Three of the following statements about enzymes are correct and one is wrong. Which one is wrong?


(1) Enzymes require optimum pH for maximal activity

(2) Enzymes are denatured at high temperature but in certain exceptional organisms they are effective evenat temperatures 80°-90°C

(3) Enzymes are highly specific

(4) Most enzymes are proteins but some are lipids

Sol. Answer (4)

Because most enzymes are protein but some are RNA i.e. Ribonuclease-P and ribozyme.

27. Which one of the following pairs is wrongly matched? [AIPMT (Prelims)-2009]

(1) Alcohol – Nitrogenase

(2) Fruit juice – Pectinase

(3) Textile – Amylase

(4) Detergents – Lipase

Sol. Answer (1)

28. Carbohydrates are commonly found as starch in plant storage organs. Which of the following five properties

of starch (a - e) make it useful as a storage material? [AIPMT (Prelims)-2008]

a. Easily translocated b. Chemical non-reactive

c. Easily digested by animals d. Osmotically inactive

e. Synthesized during photosynthesis

The useful properties are

(1) Both a & e (2) Both b & c (3) Both b & d (4) a, c & e

Sol. Answer (3)

Carbohydrates like glycogen and starch are relatively easy to store because of the following advantages.

• They are stored in bulk.

• They are chemically non-reactive.

• They are osmotically inactive.

29. An organic substance bound to an enzyme and essential for its activity is called [AIPMT (Prelims)-2006]

(1) Coenzyme (2) Holoenzyme

(3) Apoenzyme (4) Isoenzyme

Sol. Answer (1)

Organic compound which bound to an enzyme is either coenzyme or prosthetic group.



30. Telomerase is an enzyme which is a : [AIPMT (Prelims)-2005]

(1) Repetitive DNA (2) RNA (3) Simple protein (4) Ribonucleoprotein

Sol. Answer (4)

31. Which of the following is the simplest amino acid? [AIPMT (Prelims)-2005]

(1) Tyrosine (2) Asparagine (3) Glycine (4) Alanine

Sol. Answer (3)

Because in glycine, the R-group is replaced by hydrogen.

HOOC C

H

NH2

H = R group

32. Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all ofthese [AIPMT (Prelims)-2005]

(1) Enhance oxidative metabolism

(2) Are conjugated proteins

(3) Are exclusively synthesized in the body of a living organism as at present

(4) Help in regulating metabolism

Sol. Answer (4)

(1) is incorrect, because enzymes can both enhance and inhibit the oxidative metabolism.

(3) is incorrect, different enzymes, vitamins and hormones are synthesized in the body at different situations.

(2) is incorrect, because all hormones and enzymes are not conjugated protein.

33. Carbohydrates, the most abundant biomolecules on earth, are produced by [AIPMT (Prelims)-2005]

(1) All bacteria, fungi and algae (2) Fungi, algae and green plant cells

(3) Some bacteria, algae and green plant cells (4) Viruses, fungi and bacteria

Sol. Answer (3)

Autotrophic organism produce glucose by photosynthesis which is a carbohydrate. Heterotrophic are dependenton autotrophes and don't produce carbohydrate and fungi are saprobic organisms.

34. Which of the following statements regarding enzyme inhibition is correct ? [AIPMT (Prelims)-2005]

(1) Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate

(2) Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein

(3) Competitive inhibition is seen when the substrate and the inhibitor compete

(4) Non-competitive inhibitors often bind to the enzyme irreversibly

Sol. Answer (3)

(1) is wrong, because competitive inhibition of an enzyme can be overcome by adding large amount ofsubstrate.

(2) is wrong, because competitive inhibtion is seen when a substrate competes with an inhibitor for bindingto the active site of enzyme.

(4) is wrong, because non-competitive inhibitor often bind to enzyme irreversibly.



35. The catalytic efficiency of two different enzymes can be compared by the [AIPMT (Prelims)-2005]

(1) The Km value (2) The pH optimum value

(3) Formation of the product (4) Molecular size of the enzyme

Sol. Answer (1)

36. The four elements that make up 96% of all the elements found in a living system are

(1) C, H, O and P (2) C, N, O and P (3) H, O, C and N (4) C, H, O and S

Sol. Answer (3)

% weight of human body : C = 18.5; O = 65.0; N = 3.3; H = 0.5

37. High cholesterol patients are advised to use

(1) Ghee, butter and oils (2) Groundnut oil, margarine and vegetable oils

(3) Fatty oil and butter (4) Cheese, dalda and ghee

Sol. Answer (2)

Because these oils contain polyunsaturated fatty acids (i.e. more than one double bond) and they are usuallyrecommended by doctors to person having hypertension, high blood cholesterol and other cardiovasculardiseases.

38. Essential amino acid is

(1) Phenylalanine (2) Glycine (3) Aspartic acid (4) Serine

Sol. Answer (1)

Essential amino acids are leucine, isoleucine, valine, tryptophane, phenylalanine, lysine and methionine.

39. Lipids are insoluble in water because lipid molecules are

(1) Hydrophilic (2) Hydrophobic (3) Neutral (4) Zwitter ions

Sol. Answer (2)

Hydro-means water, phobic - means repeling or hating

Lipids are hydrophobic that's why they are not soluble in water.

40. The major role of minor elements inside living organisms is to act as

(1) Co-factors of enzymes (2) Building blocks of important amino acids

(3) Constituents of hormones (4) Binders of cell structure

Sol. Answer (1)

Minor elements basically includes Zn, Mg, K, Ni, Co, NAD+, NADP+, they all come under the category ofcofactor.

41. Nucleotides are building blocks of nucleic acids. Each nucleotide is a composite molecule formed by

(1) Base-sugar-phosphate (2) Base-sugar-OH

(3) (Base-sugar-phosphate)n

(4) Sugar-phosphate

Sol. Answer (1)

Nucleotide : Base + Sugar + Phosphate

Nucleic acid : (Base + Sugar + Phosphate)n

42. About 98 percent of the mass of every living organism is composed of just six elements including carbon,hydrogen, nitrogen, oxygen and

(1) Sulphur and magnesium (2) Magnesium and sodium

(3) Calcium and phosphorus (4) Phosphorus and sulphur

Sol. Answer (3)



43. Which of the following is a neutral amino acid?

(1) Glutamine (2) Arginine (3) Valine (4) Asparagine

Sol. Answer (3)

Glutamine, Asparagine → Amide group containing amino-acid.

Arginine → Basic amino acid

44. The most unsaturated fatty acid is

(1) Linoleic acid (2) Oleic acid (3) Linolenic acid (4) Arachidonic acid

Sol. Answer (4)

Arachidonic acid : It is 20 C containing unsaturated fattty acid (C20

H32

O2) with four double bond.

Oleic acid – 1 double bond

Linoleic acid – 2 double bonds

Linolenic acid – 3 double bonds

45. Which of the following is a nucleotide?

(1) Thymidine (2) Cytosine (3) Thiamine (4) Uridylic acid

Sol. Answer (4)

Thymidine – Nucleoside; Thiamine – Vitamin; Cytosine – Nitrogen base; Uridylic acid – Nucleotide

46. Which of the following is incorrect regarding the amino acids and their functions?

(1) Tyrosine : Converted into epinephrine hormone and used in the synthesis of melanin pigment

(2) Glycine : Involved in the formation of heme

(3) Tryptophan : Helps in the synthesis of auxin hormone

(4) Histidine : Can be converted into histamine by the removal of amino group

Sol. Answer (4)

Histamine is derived from amino acid histidine through decarboxylation.

47. Which of the following is the diagrammatic representation of phospholipid lecithin?

(1)

CH – O – C – R2 1

CH – O – C – R2

O

CH – O – P – O – CH – CH – NH2 2 2 3

+

O

OH

O

(2)

CH – O – C – R2 1

CH – O – C – R2

O

CH – O – C – R2 3

O

O

(3)

CH – O – C – R2 1

CH – O – C – R2

O

CH – O – P – O – CH – CH – N – CH2 2 2 3

O

OH

O

CH3

CH3

+

(4)

CH – O – C – R2 1

R – C – O – 2

CH

O

CH – O – P – OH2

O

O

OH

Sol. Answer (3)

Lecithin is a phospholipid present in cell membrane



48. Which of the following is not a secondary metabolite of plant cell?

(1) Rubber (2) Chlorophyll (3) Essential oil (4) Tannins

Sol. Answer (2)

Rubber → Polymeric substance

Essential oil

Tannins → Pigments

49. The most abundant molecule in cell is

(1) Water (2) Carbohydrate (3) Lipid (4) Protein

Sol. Answer (1)

Water = 70 – 90% of the total cellular mass

Carbohydrate = 3%

Lipid = 2%

Protein = 10–15%

50. Which are the most diverse molecules in the cell?

(1) Lipids (2) Mineral salts (3) Proteins (4) Carbohydrates

Sol. Answer (3)

Because protein are made up of 20 different amino acids and are heteropolymers of amino acids.

51. The most abundant organic compound on earth is

(1) Protein (2) Cellulose (3) Lipids (4) Steroids

Sol. Answer (2)

Plant cell wall is made up of cellulose.

52. Haemoglobin is a type of

(1) Carbohydrate (2) Respiratory pigment (3) Vitamin (4) Skin pigment

Sol. Answer (2)

Because haemoglobin get binds to oxygen and help in the transportation of O2.

53. Collagen is

(1) Fibrous protein (2) Globular protein (3) Lipid (4) Carbohydrate

Sol. Answer (1)

Because collagen are thread like proteins, which are insoluble in water.

54. Maltose is formed of two molecules of

(1) Fructose (2) Lactose (3) Glucose (4) Sucrose

Sol. Answer (3)

Fructose = Monosaccharides

Lactose = Galactose + Glucose

Sucrose = Glucose + Fructose

Maltose = Glucose + Glucose



55. A polysaccharide which is synthesized and stored in liver cells is

(1) Arabinose (2) Glycogen (3) Lactose (4) Galactose

Sol. Answer (2)

Glycogen is a polymer of glucose.

56. Agar is commercially obtained from

(1) Red algae (2) Blue-green algae

(3) Brown algae (4) Green algae

Sol. Answer (1)

Agar is a type of mucopolysaccharide and is obtained from red algae. It is used as culture medium in

laboratory.

57. Which of the following groups consists of polysaccharides only?

(1) Sucrose, glucose and fructose (2) Maltose, lactose and fructose

(3) Glycogen, sucrose and maltose (4) Glycogen, cellulose and starch

Sol. Answer (4)

Sucrose → Disaccharide; Fructose → Monosaccharide

Glucose → Monosaccharide; Maltose → Disaccharide

Lactose → Disaccharide; Glycogen → Polysaccharide

Cellulose → Polysaccharide; Starch → Polysaccharide

58. Lactose is composed of

(1) Glucose + galactose (2) Fructose + galactose

(3) Glucose + fructose (4) Glucose + glucose

Sol. Answer (1)

Lactose is a disaccharide.

59. Cellulose, the most important constituent of plant cell wall is made up of

(1) Branched chain of glucose molecules linked by α1, 4 glycosidic bond in straight chain andα1, 6 glycosidic bond at the site of branching

(2) Unbranched chain of glucose molecules linked by β1, 4 glycosidic bond

(3) Branched chain of glucose molecules linked by α1, 6 glycosidic bond at the site of branching

(4) Unbranched chain of glucose molecules linked by α1, 4 glycosidic bond

Sol. Answer (2)

Glycogen and starch are branched polymer of glucose while cellulose is unbranched polymer of β glucose.

60. A person is eating boiled potato. His food contains

(1) Cellulose, which can be digested by cellulase

(2) Starch, which cannot be digested

(3) Lactose, which cannot be digested

(4) DNA, which can be digested by pancreatic DNAase



Sol. Answer (4)

(1) is wrong, because our gut can't produce cellulose.

(2) is wrong because potato contain starch and it can be digested.

(3) is wrong, because lactose is absent in potato.

61. Which of the following is a reducing sugar?

(1) Galactose (2) Gluconic acid (3) β-methyl galactoside (4) Sucrose

Sol. Answer (1)

Because it can reduce Cu2+ ions into Cu+ ion.

62. An important step in the manufacture of pulp for paper industry is the

(1) Preparation of pure cellulose

(2) Treatment of wood with chemicals that break down cellulose

(3) Removal of oils present in the wood by treatment with suitable chemicals

(4) Removal of water from the wood by prolonged heating at approximately 50°C

Sol. Answer (1)

Because the raw material for paper is cellulose.

63. β1-4 linkages are present in

(1) Cellulose (2) Chitin (3) Starch (4) Both (1) & (2)

Sol. Answer (4)

Cellulose – β(1, 4) linkage (β-glucose)

Chitin – β(1, 4) linkage (N-acetyl glucosamine)

Starch – α(1, 4) (in straight chain) of amylose and amylopectin

α(1, 6) (at branching)

64. Which of the following statements is false?

(1) Cellulose is the most abundant organic compound in the biosphere

(2) Cellulose is an unbranched polymer with β-1,4 glycosidic bonds

(3) Rayon and cellophane are chemically similar to cellulose xanthate

(4) Cellulose can be digested by the herbivores by β-amylase, produced by the glandular cells of theiralimentary canal

Sol. Answer (4)

Cellulose can be digested by the herbivores because they have special type cellulose digesting micro-organismfor the digestion of cellulose.

65. If the total amount of adenine and thymine in a double-stranded DNA is 60%, the amount of guanine in thisDNA will be

(1) 15% (2) 20% (3) 30% (4) 40%

Sol. Answer (2)

A + T = 60%

Then, C + G = 40%, when 20% ⇒ C and 20% = G

66. DNA has equal number of adenine and thymine residues (A = T) and equal number of guanine and cytosine(G = C). These relationships are known as

(1) Chargaff's rule (2) Coulomb's law

(3) Le Chatelier's principle (4) Van't Hoff plot

Sol. Answer (1)



67. Which of the following pairs of nitrogenous bases of nucleic acids is mismatched with the category mentionedagainst it?

(1) Adenine, Thymine – Purines (2) Thymine, Uracil – Pyrimidines

(3) Uracil, Cytosine – Pyrimidines (4) Guanine, Adenine – Purines

Sol. Answer (1)

Adenine and Guanine → Purines

Thymine, uracil, cytosine → Pyrimidines

68. In a DNA molecule

(1) There are two strands which run antiparallel-one in 5′ → 3′ direction and other in 3′ → 5′

(2) The total amount of purine nucleotides and pyrimidine nucleotides is not always equal

(3) There are two strands which run parallel in the 5′ → 3′ direction

(4) The proportion of adenine in relation to thymine varies with the organism

Sol. Answer (1)

In DNA, two antiparallel strands are coiled around a common axis.

69. Which purine base is found in RNA?

(1) Thymine (2) Uracil (3) Cytosine (4) Guanine

Sol. Answer (4)

Because Thymine → Present in DNA, not in RNA

Cytosine, uracil → Pyrimidine

70. Similarity in DNA and RNA is that

(1) Both are polymers of nucleotides (2) Both have similar pyrimidines

(3) Both have similar sugar (4) Both are genetic material in man

Sol. Answer (1)

Nucleotide is a monomeric unit of nucleic acid.

71. Length of one loop of B-DNA is

(1) 3.4 nm (2) 0.34 nm (3) 20 nm (4) 10 nm

Sol. Answer (1)

Pitch of B-DNA = 34 Å ⇒ 3.4 nm (∵ 1 Å = 0.1 nm)

72. Which of the following enzymes is used to join bits of DNA?

(1) Ligase (2) Primase

(3) DNA polymerase (4) Endonuclease

Sol. Answer (1)

Class VI → Ligase enzyme is used to join the bits of DNA.

Primase → Is an enzyme use to attach primer.

DNA polymerase → is an enzyme use to add nucleotide in template strand of DNA.

Endonuclease → It is an restriction enzyme which causes internal cleavage of DNA.



73. The 3′-5′ phosphodiester linkages inside a polynucleotide chain serve to join

(1) One DNA strand with the other DNA strand

(2) One nucleoside with another nucleoside

(3) One nucleotide with another nucleotide

(4) One nitrogenous base with pentose sugar

Sol. Answer (3)

Because nucleotide is a monomeric unit of nucleic acid which are joined together by 3' – 5' phosphodiester bond.

74. ATP is

(1) Nucleotide (2) Nucleoside (3) Nucleic acid (4) Vitamin

Sol. Answer (1)

Because ATP (Adenosine triphosphate) is made up of adenine, ribose sugar and 3 phosphate groups.

75. The role of an enzyme in a reaction is to/as

(1) Decrease activation energy (2) Increase activation energy

(3) Inorganic catalyst (4) None of these

Sol. Answer (1)

Substrate energy

Product

Progress of reaction

Potential energy

Transition state

Activation energy without enzyme

Activation energy with enzyme

76. Which of the following factor(s) do(es) not affect enzyme activity?

A. Temperature B. pH

C. Enzyme concentration D. Product concentration

E. Substrate concentration F. Activation energy

(1) C only (2) C & D (3) D only (4) F only

Sol. Answer (4)

Because enzyme activity is affected by temperature, pH, enzyme concentration, product concentration andsubstrate concentration.

Enzyme are not affected by activation energy but it lowers down the activation energy.

77. A competitive inhibitor of succinic dehydrogenase is

(1) Malate (2) Malonate (3) Oxaloacetate (4) Both (2) & (3)

Sol. Answer (4)

Competitive inhibitors of succinic dehydrogenase are malate, malonate, oxaloacetate.



78. Which of the following is a typical example of ‘feedback inhibition’?

(1) Cyanide and cytochrome reaction

(2) Sulpha drugs and folic acid synthesizer bacteria

(3) Allosteric inhibition of hexokinase by glucose 6-phosphate

(4) Reaction between succinic dehydrogenase and succinic acid

Sol. Answer (3)

(1) Cyanide and cytochrome reaction → Example of non-competitive inhibition.

(2) Sulpha drugs and folic acid synthesizer bacteria are example of non-competitive inhibition.

(4) Reaction between succinic dehydrogenase and succinic acid are example of competitive inhibition.

79. Which factor is responsible for inhibition of enzymatic process during feedback?

(1) Substrate (2) Enzyme (3) End product (4) Temperature

Sol. Answer (3)

Feedback inhibition is also konwn as End product inhibition or allosteric modulation.

80. Which of the following is true for competitive enzyme inhibition?

(1) Decrease in Vmax

and Km

(2) Unchanged Vmax

and decrease in Km

(3) Unchanged Vmax

and increase in Km

(4) Increase in Vmax

and Km

Sol. Answer (3)

Vmax

= constant; Km

= increased

Vmax

Vmax

2

NoInhibitor

Km [S]

With inhibitor

Km'

Reaction velocity

81. The Michaelis constant Km is

(1) Numerically equal to ½ Vmax

(2) Dependent on the enzyme concentration

(3) Numerically equal to the substrate concentration that gives half maximal velocity

(4) Increased in the presence of non-competitive inhibitor

Sol. Answer (3)

vmax

Km

[s]

vmax

2

Velocityof reaction



82. If an enzyme has been given the EC code 5.2.1.7, it is likely to be involved in

(1) Digestion (2) Redox reaction (3) Isomerization (4) Molecular breakdown

Sol. Answer (3)

EC code 5.2.1.7, in this the first digit represents class of enzyme.

And the class V of enzyme is isomerases, which catalyse the isomerisation reaction.

83. Prosthetic group is a part of holoenzyme. It is

(1) Loosely attached organic part

(2) Loosely attached inorganic part

(3) Non-protein organic part firmly attached with apoenzyme

(4) None of these

Sol. Answer (3)

Enzyme (Holoenzyme)

Protein(Apoenzyme)

Non-protein (Cofactor)

Inorganic compoundOrganic compound

Loosely bound(Coenzyme)



., Zn , Mg , etc.i.e2+ 2+

Ca2+

84. Which of the following has carbohydrate as prosthetic group?

(1) Glycoprotein (2) Chromoprotein

(3) Lipoprotein (4) Nucleoprotein

Sol. Answer (1)

It is a conjugated protein in which protein is conjugated with carbohydrate.

85. Mark the mismatched pair.

(1) Cellulose : Unbranched polymer with β,1-4 glycosidic linkage

(2) Cellophane : Cellulose xanthate

(3) Carboxypeptidase : Exopeptidase, Mg2+ acts as a co-factor

(4) Aminopeptidase : Exopeptidase, cleaves the peptide bond at N-terminal end

Sol. Answer (3)

Carboxypeptidase requires Zn2+ as cofactor.

86. Apoenzyme is

(1) Always a protein (2) Often a metal

(3) Always an inorganic compound (4) Often a vitamin

Sol. Answer (1)

Protein part of enzyme is known as apoenzyme and non-protein part of enzyme is known as cofactor.



SECTION - D

Assertion-Reason Type Questions

1. A : Cofactor of an enzyme may be a prosthetic group.

R : NAD derived from niacin is a co-enzyme.

Sol. Answer (2)

Organic compound firmly attach to protein part of enzyme is prosthetic group.

2. A : Linolenic acid is an essential fatty acid.

R : Linolenic acid cannot be synthesised in human beings.

Sol. Answer (1)

PUFA (Polyunsaturated Fatty Acids) are essential fatty acid.

3. A : Hormones are not enzymes, but they can stimulate the release of enzymes.

R : Hormones are used up in metabolism, but enzymes can act over and over again.

Sol. Answer (2)

Enzymes are not used up in metabolism.

4. A : Tertiary structure of protein molecules makes them biologically active.

R : It is native configuration of protein molecules maintained by multiple covalent bonds only.

Sol. Answer (3)

Because enzyme exists in tertiary structure in which sides group comes close and form an active site.

5. A : Dextrins are intermediate polysaccharides formed during hydrolysis of starch into sugar.

R : Ascorbic acid is a sugar derivative.

Sol. Answer (2)

Ascorbic acid is sugar acid.

6. A : Non-competitive inhibitors have no effect on Vmax

.

R : In non-competitive inhibition, inhibitor and substrate bind at same sites on the enzyme.

Sol. Answer (4)

Non-competitive inhibitors decrease Vmax

.

7. A : The polypeptide coil of collagen helix is strengthened by the estabilishment of hydrogen bond between >NH - group of glycine residue of each strand with –CO group of other two strand.

R : In collagen helix locking effect also occurs with the help of proline and hydroxyproline amino acid.

Sol. Answer (2)

In collagen, there are generally three polypeptides coil around one another.

8. A : Allosteric enzymes do not show a typical Michaelis Menten constant or behaviour.

R : All enzymes work at same pH.

Sol. Answer (3)

Allosteric enzymes don't obey Michaelis Menten constant.



9. A : α amylase of wheat endosperm has 16 isoenzymes.

R : In competitive inhibition Vmax

decreases.

Sol. Answer (3)

Isoenzymes are the isomeric form of same enzyme.

10. A : Tertiary structure of protein is absolutely necessary for many biological activities of proteins.

R : In protein, only right handed helices are observed.

Sol. Answer (2)

Enzymes have tertiary structure of protein.

� � �


Solutions

SECTION - A


(Digestive System)

1. The major components of food are

(1) Carbohydrates (2) Proteins (3) Fats (4) All of these

Sol. Answer (4)

Carbohydrates, fats and proteins are macronutrients or proximate principles of food because these components

constitute the energy source for the production of heat and different organic function and are required in large

quantity in our body.

2. In which type of dentition, each tooth in the buccal cavity is embedded in a socket of jaw bone?

(1) Heterodont (2) Thecodont (3) Diphyodont (4) Monophyodont

Sol. Answer (2)

Because thecodont is a condition in which teeth are embedded in sockets and have well developed roots.

Monophyodont : Teeth which come once in life.

Diphyodont : Teeth which come twice in life.

Heterodont : Human (Adult) has 32 permanent teeth which are of four different types i.e., incisors, canines,

premolars, molars. Such type of dentition is called Heterodont.

3. The dental formula of human beings is

(1)2123

2123(2)

2021

2021(3)

2321

2321(4)

2133

2133

Sol. Answer (1)

2123

2123

Incisors Canines Premolars Molars

(Adult)2102

2102 (Childhood)

4. The common passage for food and air is

(1) Oesophagus (2) Pharynx (3) Trachea (4) Glottis

Chapter 3

Digestion and Absorption

50 Digestion and Absorption Solutions of Assignment


Sol. Answer (2)

Pharynx is a common passage for food and air.

Oesophagus : Food pipe.

Trachea : Wind pipe

Glottis : Opening of larynx that remains covered by epiglottis during swallowing.

5. All of the following are the parts of large intestine, except

(1) Caecum (2) Colon (3) Ileum (4) Rectum

Sol. Answer (3)

Because Ileum is a part of small intestine.

6. Oesophagus opens in which part of the stomach?

(1) Pyloric (2) Cardiac (3) Fundic (4) Caecum

Sol. Answer (2)

Oesophagus

Fundus

Cardiac

Pyloric

Superior portionof duodenum

7. How many pairs of salivary glands are present in human beings?

(1) 2 pairs (2) 3 pairs (3) 4 pairs (4) 5 pairs

Sol. Answer (2)

Three pairs of salivary glands are :

(1) Parotid (1 pair)

(2) Sub-maxillary / sub-mandibular (1 pair)

(3) Sub-lingual (1 pair)

8. Which gland is both exocrine and endocrine?

(1) Liver

(2) Gall bladder

(3) Glisson’s capsule

(4) Pancreas

Sol. Answer (4)

As pancreas is a compound gland. So it acts as exocrine and endocrine gland both.

9. Glisson’s capsule is related to

(1) Liver (2) Pancreas (3) Lung (4) Pharynx

Sol. Answer (1)

Glisson's capsule is a thin connective sheath which covers hepatic lobule.

51Solutions of Assignment Digestion and Absorption


10. Endocrine portion of pancreas secretes

(1) Insulin

(2) Glucagon

(3) Both (1) & (2)

(4) HCl

Sol. Answer (3)

α-Cells of pancreas → Secrete glucagon

β-Cells of pancreas → Secrete insulin

δ-Cells of pancreas → Secrete somatostatin

11. Bile is stored and concentrated in

(1) Liver (2) Pancreas (3) Lungs (4) Gall bladder

Sol. Answer (4)

Gall bladder : It removes water and not Na+ ions from bile and concentrate it.

12. Which organ of the following is present in abdominal cavity, just below diaphragm.

(1) Pharynx (2) Pancreas (3) Liver (4) Tongue

Sol. Answer (3)

Liver is the largest gland of the body, which is situated in the abdominal cavity, just below the diaphragm. It

has two lobes i.e., right and left lobes.

13. Which is the largest gland of human body?

(1) Liver (2) Pancreas (3) Gall bladder (4) Lung

Sol. Answer (1)

Liver is the largest gland of the body weighing about 1.2 to 1.5 kg in adult human.

14. The wall of alimentary canal from oesophagus to rectum possesses _____ layers.

(1) 2 layers (2) 3 layers (3) 4 layers (4) 5 layers

Sol. Answer (3)

Four layers

SerosaMuscularisSub-mucosaMucosa

Wall of alimentary canal

15. The major functions of buccal cavity is/are

(1) Mastication of food

(2) Facilitation of swallowing

(3) Help in the secretion of glucagon

(4) Both (1) & (2)

Sol. Answer (4)

(1) Mastication of food → Function of buccal cavity

(2) Facilitation of swallowing → Function of buccal cavity

(3) Help in secretion of glucogon → Function of α-cell of pancreas.



(Digestion of Food)

16. The antibacterial enzyme, present in the saliva that prevents infections is

(1) Maltose

(2) Salivary amylase

(3) Lysozyme

(4) Pepsinogen

Sol. Answer (3)

Maltose → Sugar

Salivary amylase → Help in digestion of carbohydrate

Pepsinogen → Inactive form of pepsin, which help in digestion of protein.

17. HCl secreting cells present in the stomach are

(1) Oxyntic cells (2) Peptic cells (3) Chief cells (4) Mucus neck cells

Sol. Answer (1)

Peptic or chief cell : Secrete the proenzyme pepsinogen

Mucus neck cell : Secrete mucus

Pepsinogen : Oxyntic or parietal cells : Secret HCl and intrinsic factor.

18. Which enzyme gets activated by HCl, secreted from gastric glands?

(1) Trypsinogen (2) Pepsinogen (3) Renin (4) Chymotrypsin

Sol. Answer (2)

EnterokinaseTrypsinogen Trypsin⎯⎯⎯⎯⎯⎯→

HClPepsinogen Pepsin⎯⎯⎯→

TrypsinChymotrypsinogen Chymotrypsin⎯⎯⎯⎯→

Renin → Hormone which help in osmoregulation

19. All of the following juices contain enzymes, except

(1) Pancreatic juice

(2) Intestinal juice

(3) Bile juice

(4) Gastric juice

Sol. Answer (3)

Because bile contains bile pigments (bilirubin and biliverdin), bile salts (sodium bicarbonate, sodium

glycocholate, sodium taurocholate), cholesterol and phospholipids.

20. The breakdown of biomolecules i.e. dipeptides, lactose, maltose and sucrose etc. occur mainly in the

(1) Ilium

(2) Pyloric region of stomach

(3) Duodenum region of small intestine

(4) Caecum region of large intestine



Sol. Answer (3)

Duodenum region of small intestine. Because the enzyme requires of the breakdown of biomolecules i.e.

dipeptides, lactose, maltose and sucrose are present in the succus entericus (intestinal juice).

21. Enzyme lactase is responsible for the breakdown of lactose into

(1) Glucose + Fructose

(2) Glucose + Galactose

(3) Glucose + Glucose

(4) Fatty acids + Glycerol

Sol. Answer (2)

lactoseLactose Glucose + Galactose⎯⎯⎯⎯→

22. Crypts of Lieberkuhn are present in

(1) Stomach

(2) Pharynx

(3) Oesophagus

(4) Intestine

Sol. Answer (4)

Crypts of Lieberkuhn, which are also known as intestinal glands, are present in intestine.

23. The main function of bile is to

(1) Eliminate the waste products

(2) Emulsify the fats

(3) Digest proteins by enzymatic activity

(4) Regulate the digestion process

Sol. Answer (2)

Bile helps in emulsification of fats i.e., breakdown of the fats into very small micelles. As, Bile do not have

any enzyme, so it does not help in digestion of protein.

24. The wave like muscular contractions of the digestive tract is called

(1) Mastication (2) Assimilation (3) Peristalsis (4) Stimulation

Sol. Answer (3)

During the oesophageal phase of swallowing, food is pushed through the oesophagus by involuntary muscular

movements called peristalsis.

Mastication : Chewing of food.

Assimilation : When the absorbed food material in blood and lymph, will reach to tissue, which we utilise

them for our activity like growth, energy and repair.

25. Enzyme trypsinogen is a component of

(1) Mucus (2) Saliva (3) Pancreatic juice (4) Intestinal juice



Sol. Answer (3)

Trypsinogen is inactive form of trypsin.

26. The food that enters into intestine from stomach is

(1) Alkaline chyle (2) Fundus (3) Acidic chyme (4) Bolus

Sol. Answer (3)

Because the pH of stomach is low (1.8-3.2) and the food that passes from stomach also get acidic because

of the presence of HCl.

(Absorption of Digested Product, Disorder of Digestive System)

27. Absorption of substances takes place in different parts of the alimentary canal. However maximum absorption

takes place in

(1) Small intestine (2) Large intestine (3) Transverse colon (4) Ascending colon

Sol. Answer (1)

Absorption of substances takes place in different parts of the alimentary canal, like mouth, stomach, small

intestine and large intestine. But maximum absorption occurs in the small intestine.

28. Absorption of water, simple sugars and alcohol etc. takes place in

(1) Mouth (2) Stomach (3) Rectum (4) Large intestine

Sol. Answer (2)

Absorption of substance takes place in different parts of the alimentary canal :

Mouth : Some drugs

Stomach : Water, simple sugar, alcohol, drugs.

Small Intestine : Water, amino acid, sugar, glycerol, fatty acid, minerals, vitamin.

Large intestine : Water, some mineral, drugs.

29. In intestine, the function of microvilli is to

(1) Secrete gastric juice (2) Secrete pancreatic juice

(3) Increase absorptive surface area (4) Secrete hormones

Sol. Answer (3)

Microvilli increase absorptive surface area.

30. Abnormal frequency of bowel movement and increased liquidity of the faecal discharge is known as

(1) Vomiting (2) Diarrhoea (3) Constipation (4) Indigestion

Sol. Answer (2)

Vomiting: It is the ejection of stomach contents through the mouth.

Diarrhoea: The abnormal frequency of bowel movement and increased liquidity of the foecal discharge.

Constipation: In this, faeces are retained within the rectum as the bowel movements occur irregularly.

Indigestion: In this, the food is not properly digested leading to a feeling of fullness.



SECTION - B


(Digestive System)

1. Pyloric sphincter regulates the opening of

(1) Pharynx into oesophagus (2) Oesophagus into stomach

(3) Stomach into duodenum (4) Ileum into large intestine

Sol. Answer (3)

Pyloric sphincter present in the pyloric region of the stomach which regulates the opening of stomach into

duodenum.

2. The structural and functional unit of liver is

(1) Cystic duct (2) Hepatic lobule

(3) Hepatopancreatic duct (4) Sphincter of Oddi

Sol. Answer (2)

Hepatic lobules are the structural and functional units of liver containing hepatic cells arranged in the form of

cords.

3. Match the following

Column I Column II

(Salivary gland) (Their location)

a. Parotids (i) Below tongue

b. Sub-maxillary/sub-mandibular (ii) Lower jaw

c. Sub-linguals (iii) Cheek

(1) a(i), b(ii), c(iii) (2) a(i), b(iii), c(ii) (3) a(ii), b(i), c(iii) (4) a(iii), b(ii), c(i)

Sol. Answer (4)

Parotid - Present near cheek

Sub-maxillary/sub - Mandibular - Present at lower jaw

Sub-linguals - Present below tongue

4. Bile can be prevented to release into duodenum by

(1) Sphincter of Oddi (2) Cardiac sphincter (3) Pyloric sphincter (4) Ileo-caecal valve

Sol. Answer (1)

Because sphincter of Oddi guards the common hepatopancreatic duct, through which the bile is released into

duodenum.

5. Dental formula for the monophyodont teeth of human is

(1)2100

2100

(2)3000

3000

(3)0221

0221

(4)2021

2021



Sol. Answer (1)

Monophyodont 0021

0021⇒

Incisors Canines Premolars Molars

2102

2102⇒Diphyodont

6. Upper molars in human dentition have

(1) Four roots (2) Three roots (3) Two roots (4) Single root

Sol. Answer (2)

Root formula =1 1 2 3

1 1 1 2

→ Upper jaw

→ Lower jaw

7. Which of the following can be taken as true stomach in ruminants?

(1) Rumen (2) Reticulum (3) Omasum (4) Abomasum

Sol. Answer (4)

In ruminants, abomasum is a true stomach which secrete gastric juice and release all enzyme here.

8. Oblique muscle layer is present in

(1) Stomach (2) Duodenum (3) Colon (4) All of these

Sol. Answer (1)

An oblique muscle layer is found inner to the circular muscle layer in stomach.

9. Sphincter of Boyden which helps in the filling up of gall bladder is present in

(1) Ductus choledoccus (2) Duct of Wirsung (3) Ampulla of Vater (4) Duct of Santorini

Sol. Answer (1)

Sphincter of Boyden present in ductus choledoccus (common bile duct), help in filling up of gall bladder. The

sphincter opens to release the bile into hepatopancreatic duct.

10. Thecodont teeth are present in

a. Sphenodon b. Crocodiles c. Mammals d. Scoliodon

(1) c only (2) b & c only (3) a, b, & c only (4) a, b, c & d

Sol. Answer (2)

Crocodiles and mammals → Thecodont teeth

Sphenodon and Scoliodon → Acrodont teeth

11. Cholecystitis refers to

(1) Gall bladder (2) Stomach (3) Spleen (4) Lungs

Sol. Answer (1)

Cholecystitis refers to inflammation of gall bladder.

(Digestion of Food)

12. Which carbohydrate splitting enzyme initiates the chemical process of digestion in the oral cavity?

(1) Lysozyme (2) Salivary amylase (3) Pepsin (4) Rennin

Sol. Answer (2)

Lysozyme, pepsin, rennin, they are not carbohydrate-digesting enzyme.

Salivary amylase : Only enzyme produced in buccal cavity that starts carbohydrate digestion.



13. The type of cells present in the gastric glands which secretes intrinsic factor?

(1) Peptic cells (2) Chief cells (3) Parietal cells (4) Both (1) & (2)

Sol. Answer (3)

Peptic cell or chief cells - Secrete pepsinogen.

Parietal or oxyntic cell - Secrete HCl and intrinsic factor which is essential for the absorption of Vit. B12

.

14. The proteolytic enzyme found in the gastric juice of infants which helps in the digestion of milk proteins is

(1) Renin (2) Rennin (3) Salivary amylase (4) Lysozyme

Sol. Answer (2)

Renin : It helps in osmoregulation

Rennin : Proteolytic enzyme found in the gastric juice of infants which helps in the digestion of protein.

Salivary amylase : help in digestion of carbohydrates.

Lysozyme : It is an antibacterial enzyme, present in saliva.

15. The pancreatic juice contains various enzymes, except

(1) Pepsinogen (2) Trypsinogen (3) Chymotrypsinogen (4) Procarboxypeptidase

Sol. Answer (1)

Because pepsinogen is secreted by chief cells of gastric glands.

16. Select the incorrect option

(1) Bilirubin and biliverdin are the bile pigments

(2) Emulsification is the breakdown of the fats into very small droplets

(3) Rennin is a proteolytic enzyme found in the pancreatic juice of infants which helps in the digestion of milk

protein

(4) Mucus and bicarbonates protect mucosal epithelium from excoriation by highly conc. HCl

Sol. Answer (3)

Rennin found in the gastric juice, not in pancreatic juice.

17. The main enzymes present in the gastric juice are

(1) Trypsin, pepsin and lipase (2) Pepsin, amylase and trypsin

(3) Pepsin, rennin and carboxypeptidase (4) Pepsin, lipase and rennin

Sol. Answer (4)

Because amylase found in mouth and pancreatic juice

Carboxypeptidase

Trypsin

⎫⎬⎭

found in pancreatic juice

18. Match the following columns

Column I Column II

a. Lysozyme (i) HCl

b. Peptic cells (ii) Antibacterial enzyme

c. Saliva (iii) Sublingual gland

d. Oxyntic cells (iv) Pepsinogen

(1) a(i), b(ii), c(iii), d(iv) (2) a(ii), b(iv), c(iii), d(i) (3) a(i), b(ii), c(iv), d(iii) (4) a(ii), b(iv), c(i), d(iii)



Sol. Answer (2)

Lysozyme – Has antibacterial activity

Peptic cell – Secrete pepsinogen

Saliva – Produced by sublingual salivary gland

Oxyntic cell – Secrete HCl

19. The digestion of which food component is affected if pancreas is removed?

(1) Carbohydrates (2) Proteins (3) Fats (4) All of these

Sol. Answer (4)

Because pancreatic juice contains amylase for the digestion of carbohydrates, trypsinogen, chymotrypsinogen

and carboxypeptidase for the digestion of proteins and lipase for lipid digestion.

20. At which site the emulsification of fat takes place?

(1) Pancreas (2) Gall bladder (3) Liver (4) Duodenum

Sol. Answer (4)

The bile juice stored in gall bladder travels through bile duct to the duodenum for emulsifying the fat.

21. One of the following ions is used for activation of ptyalin

(1) Sodium ions (2) Potassium ions (3) Chloride ions (4) None of these

Sol. Answer (3)

( )Ptyalin, pH = 6.8

Cl30%In mouth, Starch Maltose + Isomaltose + Dextrins−⎯⎯⎯⎯⎯⎯⎯→

22. Mark the odd one out

(1) Gastrin (2) Trypsin (3) Secretin (4) Enterocrinin

Sol. Answer (2)

Because trypsin is the enzyme and rest all are hormones.

23. When a piece of bread is chewed it tastes sweet because

(1) The sugar contents are drawn out (2) Saliva converts starch into maltose

(3) It does not taste sweet (4) The taste buds are stimulated by chewing

Sol. Answer (2)

Bread has carbohydrate (starch) which when chewed in mouth, will digested by salivary amylase and converts

it into maltose, which is sugar and sweet in taste.

24. Which of the following papillae are without taste buds in human tongue?

(1) Vallate (2) Fungiform (3) Fusiform (4) Filiform

Sol. Answer (4)

Filiform papillae are without taste buds in human tongue.

25. Digestion is completed in

(1) Duodenum (2) Ileum (3) Stomach (4) Cloaca

Sol. Answer (2)

It is a part of small intestine.



(Absorption of Digested Product, Disorder of Digestive System)

26. Select the incorrect option regarding digestion and absorption of substances in different parts of digestive

system

(1) In large intestine, absorption of water, some minerals and drugs takes place

(2) Absorption of water, simple sugars and alcohol takes place in stomach

(3) Small intestine is the principal organ for absorption of nutrients

(4) The digestion is completed in large intestine

Sol. Answer (4)

The digestion is completed in small intestine, the large intestine helps in absorption of water.

27. Which of the following is a modification of mucosa of alimentary canal?

(1) Villi (2) Microvilli (3) Rugae (4) All of these

Sol. Answer (4)

Brunner's gland is not a modification of mucosa, it is found in the submucosa of alimentary canal.

28. In acute constipation, purgatives that are used to stimulate intestinal peristalsis and evacuation of fluid faeces

contain salts of

(1) Sodium (2) Magnesium (3) Potassium (4) Calcium

Sol. Answer (2)

For acute constipation, purgatives containing salts of magnesium are used to stimulate intestinal peristalsis

and evacuation of fluid faeces as it increases the fluidity and volume of intestinal contents.

29. A prolonged constipation may cause

(1) Hemorrhoids (2) Ulcers (3) Cholera (4) Dysentery

Sol. Answer (1)

A prolonged constipation may cause hemorrhoids due to the rupture of blood vessel (varicose vein).

Hemorrhoids is also known as piles.

30. The blood capillaries of intestinal villi cannot absorb

(1) Glucose (2) Salts

(3) Fatty acids and glycerides (4) Amino acids

Sol. Answer (3)

Because fatty acid and glycerides being insoluble, cannot be absorbed into blood. They first converted into

chylomicrons, which are then transported into the lymph vessels (lacteals) in the villi. The lymph vessels

ultimately release the absorbed substance into the blood stream.

31. Vitamin containing cobalt cyanide linkage is

(1) A (2) B1

(3) B6

(4) B12

Sol. Answer (4)

Vitamin B12

contains cobalt cyanide linkage and thus is called a cyanocobalamin.

32. Pernicious anaemia is caused by the deficiency of ________ vitamin

(1) B1

(2) B12

(3) C (4) D

Sol. Answer (2)

Deficiency of vitamin B12

causes pernicious anaemia. It is a deadly anaemia because it is required for the

maturation of RBC, DNA synthesis and myelin sheath synthesis.



33. Beri-beri is due to deficiency of vitamin

(1) B7

(2) A (3) C (4) B1

Sol. Answer (4)

Beri-beri disease occurs due to the deficiency of vitamin B1 (Thiamine)

In this, muscle degeneration and nerve inflammation usually occur.

SECTION - C


1. Which cells of 'Crypts of Lieberkuhn' secrete antibacterial lysozyme? [NEET-2017]

(1) Argentaffin cells (2) Paneth cells (3) Zymogen cells (4) Kupffer cells

Sol. Answer (2)

– Kupffer-cells are phagocytic cells of liver.

– Zymogen cells are enzyme producing cells.

– Paneth cell secretes lysozyme which acts as anti-bacterial agent.

– Argentaffin cells are hormone producing cells.

2. Lungs are made up of air-filled sacs the alveoli. They do not collapse even after forceful expiration, becauseof [NEET-2017]

(1) Residual Volume (2) Inspiratory Reserve Volume

(3) Tidal Volume (4) Expiratory Reserve Volume

Sol. Answer (1)

Volume of air present in lungs after forceful expiration as residual volume which prevents the collapsing of alveolieven after forceful expiration.

3. A baby boy aged two years is admitted to play school and passes through a dental check-up. The dentistobserved that the boy had twenty teeth. Which teeth were absent? [NEET-2017]

(1) Incisors (2) Canines (3) Pre-molars (4) Molars

Sol. Answer (3)

Total number of teeth in human child = 20. Premolars are absent in primary dentition.

4. Which of the following options best represents the enzyme composition of pancreatic juice? [NEET-2017]

(1) Amylase, peptidase, trypsinogen, rennin

(2) Amylase, pepsin, trypsinogen, maltase

(3) Peptidase, amylase, pepsin, rennin

(4) Lipase, amylase, trypsinogen, procarboxy-peptidase

Sol. Answer (4)

Rennin and Pepsin enzymes are present in the gastric juice. Maltase is present in the intestinal juice.

5. Which of the following guards the opening of hepatopancreatic duct into the duodenum? [NEET-2016]

(1) Sphincter of Oddi (2) Semilunar valve (3) Ileocaecal valve (4) Pyloric sphincter

Sol. Answer (1)

Sphincter of Oddi guards the opening of hepatopancreatic duct into the duodenum.

6. In the stomach, gastric acid is secreted by the [NEET-2016]

(1) Acidic cells (2) Gastrin secreting cells (3) Parietal cells (4) Peptic cells

Sol. Answer (3)

In stomach, gastric acid (HCl) is secreted by parietal cells of gastric gland



7. The primary dentition in human differs from permanent dentition in not having one of the following type of teeth

[Re-AIPMT-2015]

(1) Incisors (2) Canine (3) Premolars (4) Molars

Sol. Answer (3)

Dental formula of human adult (permanent dentition) =2123

2123.

Dental formula of child (primary dentition) = 2102

2102

So premolars and third molar (last molar) are absent in primary dentition.

8. The enzyme that is not present in succus entericus is [Re-AIPMT-2015]

(1) Lipase (2) Maltase (3) Nucleases (4) Nucleosidase

Sol. Answer (3)

Succus entericus is intestinal juice contains maltase, lipase, nucleosidase. Nucleases are the enzymes ofpancreatic juice.

9. Which of the following statements is not correct? [AIPMT-2015]

(1) Acini are present in the pancreas and secrete carboxypeptidase

(2) Brunner's glands are present in the submucosa of stomach and secrete pepsinogen

(3) Goblet cells are present in the mucosa of intestine and secrete mucus

(4) Oxyntic cells are present in the mucosa of stomach and secrete HCl

Sol. Answer (2)

10. Gastric juice of infants contains [AIPMT-2015]

(1) Amylase, rennin, pepsinogen (2) Maltase, pepsinogen, rennin

(3) Nuclease, pepsinogen, lipase (4) Pepsinogen, lipase, rennin

Sol. Answer (4)

11. The initial step in the digestion of milk in humans is carried out by [AIPMT-2014]

(1) Lipase (2) Trypsin (3) Rennin (4) Pepsin

Sol. Answer (3)

The initial step in the digestion of milk in human is carried out by rennin.

12. Fructose is absorbed into the blood through mucosa cells of intestine by the process called: [AIPMT-2014]

(1) Active transport (2) Facilitated transport

(3) Simple diffusion (4) Co-transport mechanism

Sol. Answer (2)

Fructose is absorbed with the help of the carrier ions like Na+. This mechanism is called facilitated transport.

13. Select the correct match of the digested products in humans given in column I with their absorption site andmechanism in column II [NEET-2013]

Column I Column II

(1) Fructose, Na+ Small intenstine, passive absorption

(2) Glycerol, fatty acids Duodenum, move as chylomicrons

(3) Cholesterol, maltose Large intestine, active absorption

(4) Glycine, glucose Small intestine, active absorption

Sol. Answer (4)



14. Where do certain symbiotic microorganisms normally occur in human body [AIPMT (Mains)-2012]

(1) Duodenum (2) Caecum

(3) Oral lining and tongue surface (4) Vermiform appndix and rectum

Sol. Answer (2)

Caecum of large intestine is site which host the symbiotic micro-organism.

15. Anxiety and eating spicy food together in an otherwise normal human, may lead to [AIPMT (Prelims)-2012]

(1) Vomiting (2) Indigestion (3) Jaundice (4) Diarrhoea

Sol. Answer (2)

During indigestion, the food is not properly digested leading to a feeling of fullness. The cause of indigestion

are inadequate enzyme secretion anxiety, food poisoning, spicy food and over eating.

16. Which one of the following enzymes carries out the initial step in the digestion of milk in humans?


(1) Trypsin (2) Pepsin (3) Rennin (4) Lipase

Sol. Answer (3)

17. Two friends are eating together on a dining table. One of them suddenly starts coughing while swallowing some

food. This coughing would have been due to improper movement of [AIPMT (Prelims)-2011]

(1) Tongue (2) Epiglottis (3) Diaphragm (4) Neck

Sol. Answer (2)

18. Which one of the following correctly represents the normal adult human dental formula?


(1)2 1 2 3, , ,

2 1 2 3(2)

3 1 3 3, , ,

3 1 3 3(3)

3 1 3 1, , ,

3 1 2 1(4)

2 1 3 3, , ,

2 1 2 3

Sol. Answer (1)

19. One of the constituents of the pancreatic juice while poured into the duodenum in humans is


(1) Trypsin (2) Enterokinase (3) Trypsinogen (4) Chymotrypsin

Sol. Answer (3)

Trypsin is an active form of trypsinogen Enterokinase is present in intestinal juice.

In Duodenum, EnterokinaseTrypsinogen Trypsin⎯⎯⎯⎯⎯⎯→

TrypsinChymotrypsinogen Chymotrypsin⎯⎯⎯⎯→

Trypsin and chymotrypsin are not present in pancreatic juice, their inactive form is present in pancreatic juice.

20. If for some reason our goblet cells are non-functional this will adversely affect [AIPMT (Prelims)-2010]

(1) Smooth movement of food down the intestine (2) Production of somatostatin

(3) Secretion of sebum from the sebaceous glands (4) Maturation of sperms

Sol. Answer (1)

Because goblet cells secrete mucus.



21. Carrier ions like Na+ facilitate the absorption of substances like [AIPMT (Prelims)-2010]

(1) Fructose and some amino acids (2) Amino acids and glucose

(3) Glucose and fatty acids (4) Fatty acids and glycerol

Sol. Answer (2)

Amino acids and glucose both are absorbed by carrier mediated facilitated transport.

22. If for some reason the parietal cells of the gut epithelium become partially non-functional, what is likely to

happen? [AIPMT(Mains)-2010]

(1) The pancreatic enzymes and specially the trypsin and lipase will not work efficiently

(2) The pH of stomach will fall abruptly

(3) Steapsin will be more effective

(4) Proteins will not be adequately hydrolysed by pepsin into proteoses and peptones

Sol. Answer (4)

Oxyntic cell → Secretes HCl

Pepsinogen HCl⎯⎯→ Pepsin(active)

Protein Pepsin⎯⎯⎯⎯→ Proteoses + Peptones

So, if for some reason, the oxyntic cells of the gut epithelium become partially non-functional, then protein

will not be adequately hydrolysed by pepsin into proteoses and peptones.

23. Jaundice is a disorder of [AIPMT (Mains)-2010]

(1) Excretory system (2) Skin and eyes (3) Digestive system (4) Circulatory system

Sol. Answer (3)

In jaundice, the liver is affected, bile pigments like bilirubin, get increase in blood causing yellowness in skin

and eyes.

24. When breast feeding is replaced by less nutritive food low in proteins and calories; the infants below the age

of one year are likely to suffer from: [AIPMT (Prelims)-2009]

(1) Rickets (2) Kwashiorkor (3) Pellagra (4) Marasmus

Sol. Answer (4)

Marasmus occurs due to deficiency of protein and calories and it usually occurs in infant below one year of

age.

25. A young infant may be feeding entirely on mother's milk which is white in colour but the stools which the infant

passes out is quite yellowish. What is this yellow colour due to? [AIPMT (Prelims)-2009]

(1) Bile pigments passed through bile juice

(2) Undigested milk protein casein

(3) Pancreatic juice poured into duodenum

(4) Intestinal juice

Sol. Answer (1)

The yellow colour of faecal matter is due to stercobilin, which is obtained from the breakdown of bilirubin which

is a bile pigment.



26. Which one of the following statements is true regarding digestion and absorption of food in humans?


(1) Fructose and amino acids are absorbed through intestinal mucosa with the help of carrier ions like Na+.

(2) Chylomicrons are small lipoprotein particles that are transported from intestine into blood capillaries.

(3) About 60% of starch is hydrolysed by salivary amylase in our mouth.

(4) Oxyntic cells in our stomach secrete the proenzyme pepsinogen.

Sol. Answer (1)

Option 1 is wrong → Because 30% of starch is hydrolysed by salivary amylase in our mouth.

Option 2 is wrong → Because oxyntic cells secrets HCl.

Option 4 is wrong → Because chylomicrons are transported to lymph vessel (lacteals) in the villi.

27. Which one of the following pairs of food components in humans reaches the stomach totally undigested?


(1) Starch and fat (2) Fat and cellulose

(3) Starch and cellulose (4) Protein and starch

Sol. Answer (2)

The enzyme cellulase is not present and fats are digested in small intestine after emulsification with bile.

28. What will happen if the secretion of parietal cells of gastric glands is blocked with an inhibitor?


(1) Enterokinase will not be released from the duodenal mucosa and so trypsinogen is not converted to

trypsin

(2) Gastric juice will be deficient in chymosin

(3) Gastric juice will be deficient in pepsinogen

(4) In the absence of HCl secretion, inactive pepsinogen is not converted into the active enzyme pepsin.

Sol. Answer (4)

In the absence of HCl secretion, inactive pepsinogen is not converted into the active enzyme pepsin.

Parietal cells of gastric gland is responsible for the secretion of HCl and further HCl is responsible for the

conversion of pepsinogen into pepsin.

29. Which one of the following is the correct matching of the site of action on the given substrate, the enzyme acting

upon it and the end product? [AIPMT (Prelims)-2008]

(1) Stomach : Fats ⎯⎯⎯ →⎯Lipase micelles

(2) Duodenum : Triglycerides ⎯⎯⎯ →⎯Trypsin

monoglycerides

(3) Small intestine : Starch ⎯⎯⎯⎯ →⎯α Amylase

Disaccharide (Maltose)

(4) Small intestine : Proteins ⎯⎯⎯ →⎯Pepsin

Amino acids



Sol. Answer (3)

First option is wrong because

Fats Lipase⎯⎯⎯⎯→ Monoglycerides

Second option is wrong because

Triglycerides Lipase⎯⎯⎯⎯→ Monoglycerides

Second option is wrong because

In stomach, Proteins Pepsin⎯⎯⎯⎯→ Amino acids

30. Which one of the following is a fat-soluble vitamin and its related deficiency disease?


(1) Calciferol– Pellagra

(2) Ascorbic acid – Scurvy

(3) Retinol – Xerophthalmia

(4) Cobalamine – Beri-beri

Sol. Answer (3)

31. A person who is on a long hunger strike and is surviving only on water, will have:


(1) Less urea in his urine

(2) More sodium in his urine

(3) Less amino acids in his urine

(4) More glucose in his blood

Sol. Answer (1)

32. Examination of blood of a person suspected of having anaemia, shows large, immature, nucleated erythrocytes

without haemoglobin. Supplementing his diet with which of the following, is likely to alleviate his symptoms


(1) Thiamine

(2) Folic acid and cobalamine

(3) Riboflavin

(4) Iron compounds

Sol. Answer (2)

33. A patient is generally advised to specially, consume more meat, lentils, milk and eggs in diet only when he

suffers from [AIPMT (Prelims)-2005]

(1) Kwashiorkor (2) Rickets (3) Anaemia (4) Scurvy

Sol. Answer (1)

34. Secretin and cholecystokinin are digestive hormones. They are secreted in : [AIPMT (Prelims)-2005]

(1) Oesophagus (2) Ileum (3) Duodenum (4) Pyloric stomach

Sol. Answer (3)

Secretin and CCK are secreted in duodenum.



35. Which group of three of the following five statements (A-E) contain is all three correct statements regarding

beri-beri?

A. A crippling disease prevalent among the native population of sub-Sahara Africa.

B. A deficiency disease caused by lack of thiamine (vitamin B1).

C. A nutritional disorder in infants and young children when the diet is persistently deficient in essential

protein.

D. Occurs in those countries where the staple diet is polished rice.

E. The symptoms are pain from neuritis, paralysis, muscle wasting, progressive oedema, mental deterioration

and finally heart failure. [AIPMT (Prelims)-2005]

(1) A, B and D (2) B, C and E

(3) A, C and E (4) B, D and E

Sol. Answer (4)

36. Protective components of food are

(1) Minerals, vitamins and water

(2) Minerals, carbohydrate and proteins

(3) Minerals, carbohydrate and fats

(4) Vitamins, water and carbohydrate

Sol. Answer (1)

Minerals, vitamins and water are protective principles of food because although they do not provide us energy

but their deficiency cause diseases and abnormalities. Carbohydrate, protein and fats are proximate principles

of food.

37. Which of the following is correct location and function of Meissner’s plexus of intestine?

(1) Muscularis external - Peristalsis

(2) Muscularis internal - Peristalsis

(3) Submucosa - Mucosal secretions

(4) Mucosa - Mucosal secretions

Sol. Answer (3)

Meissner's plexus are located in the sub mucosa of alimentary canal and their function is mucosal secretion.

Meissner's plexus also known as Remak's plexus.

38. Which of the following is true regarding the source and nature of the enamel?

(1) Odontoblast, mesodermal (2) Odontoblast, ectodermal

(3) Ameloblast, mesodermal (4) Ameloblast, ectodermal

Sol. Answer (4)

Enamel is ectodermal in origin.

39. Choose the correct enzyme-substrate pair

(1) Lipase carbohydrate (2) Maltase lactose (3) Rennin casein (4) Amylase protein

Sol. Answer (3)

( ) ( )Renin

enzymesubstrateCasein Paracasein⎯⎯⎯⎯→



40. The following are absent in case of upper one third part of oesophagus, except

(1) Visceral peritoneum (Serosa) (2) Digestive gland

(3) Myenteric plexus (4) Skeletal muscles

Sol. Answer (4)

Because upper 1/3rd part of oesophagus is voluntary and lower 2/3rd part of oesophagus is involuntary.

Skeletal muscle are also known as voluntary muscle so they are present in the voluntary part of oesophagus

(i.e., 1/3rd part)

41. Mark the correct statement

(1) In lower one third part of oesophagus both Myenteric and Meissner’s plexus are absent

(2) Carboxypeptidase is exopeptidase acting on ‘N’ terminal end of peptide chain

(3) Galactosemia is metabolic genetic disorder due to deficiency of the enzyme uridyl transferase

(4) Nucleotidase and nucleosidase enzymes are present in pancreatic juice

Sol. Answer (3)

Statement-1 is wrong, because in upper one-third part of oesophagus both myenteric and meissner's plexusare absent.

Statement-2 is wrong, because carboxypeptidase is an exopeptidase acting on 'C' terminal end of peptidechain.

Statement-4 is wrong, because nucleotidase and nucleosidase enzymes are present in intestinal juice.

42. Sphincter of Oddi guards

(1) Hepato-pancreatic duct (2) Common bile duct (3) Pancreatic duct (4) Cystic duct

Sol. Answer (1)

The common bile duct and the pancreatic duct open together into the duodenum as the commonhepatopancreatic duct which is guarded by sphincter of Oddi.

Cystic duct → Duct of gall bladder (neck of gall bladder)

43. Which of the following is correct pairing of site of action and substrate of rennin?

(1) Mouth-starch (2) Small intestine-protein

(3) Stomach-casein (4) Stomach-fat

Sol. Answer (3)

In infants, renin acts on casein (milk protein) and converts casein to paracasein in stomach

So, site of action is stomach and substrate is casein.

44. If liver is removed, the compound which is not absorbed by mucosa of intestine.

(1) Proteins (2) Carbohydrates (3) Fats (4) Lactose

Sol. Answer (3)

If liver is removed, fats will not be absorbed by mucosa of intestine because liver produces bile juice for theemulsification of fats.

45. What is common among amylase, rennin and trypsin?

(1) These are produced in stomach (2) These act at a pH lower than 7

(3) These all are proteins (4) These all are proteolytic enzymes

Sol. Answer (3)

Amylase, rennin and trypsin, they all are digestive enzymes and enzymes are usually protein in nature

They all are not proteolytic enzymes because amylase acts on carbohydrate.



46. Hydrolytic enzymes which act in low pH are called

(1) Lipases (2) α-Amylase (3) Hydrolases (4) Peroxidase

Sol. Answer (3)

All digestive enzymes are hydrolytic enzymes but hydrolases is the only enzyme among four given optionswhich acts in low pH.

Lipases → Act in alkaline pH

α-Amylases → Act in weak acidic and alkaline medium

Peroxidase → Enzymes present in peroxisome and act on neutral pH.

47. Which of the following hydrolyses internal phosphodiesterase bonds in a polynucleotide chain?

(1) Lipase (2) Protease

(3) Endonuclease (4) Exonuclease

Sol. Answer (3)

Endonuclease is an enzyme which hydrolyses internal phosphodiesterase bonds in a polynucleotide chain.

48. Brunner’s glands are present in

(1) Stomach (2) Oesophagus

(3) Ileum (4) Duodenum

Sol. Answer (4)

Brunner's glands are located in the submucosa of duodenum

49. The enzyme enterokinase helps in the conversion of

(1) Paracasein into casein (2) Trypsinogen into trypsin

(3) Pepsinogen into pepsin (4) Proteins into polypeptides

Sol. Answer (2)

Trypsinogen Enterokinase⎯⎯⎯⎯⎯⎯→ Trypsin

Casein Renin⎯⎯⎯→ Paracasein

Pepsinogen HCl⎯⎯→ Pepsin

Protein

{ }

Proteolytic

enzyme trypsin, pepsin etc

⎯⎯⎯⎯⎯⎯⎯⎯→ Polypeptide

50. Activation of pro-carboxypeptidase into carboxypeptidase is brought about by

(1) Enterokinase (2) Endopeptidase (3) Exopeptidase (4) Trypsin

Sol. Answer (4)

Trypsinogen Enterokinase⎯⎯⎯⎯⎯⎯→ Trypsin

Procarboxypeptidase Trypsin⎯⎯⎯⎯→ Carboxypeptidase

51. Which of the following is the function of enterogastrone?

(1) It inhibits the secretion of gastric juice

(2) It stimulates the secretion of digestive juice in the stomach

(3) It stimulates the flow of pancreatic juice

(4) It regulates the flow of bile



Sol. Answer (1)

It inhibits the secretion of gastric juice. Because enterogastrone is a gastric inhibitory protein, which acts onstomach and inhibits the gastric juice secretion.

52. The contraction of gall bladder is caused by

(1) Cholecystokinin (2) Enterogastrone

(3) Gastrin (4) Secretin

Sol. Answer (1)

Cholecystokinin is a hormone, which acts on gall bladder and stimulates the contraction of gall bladder torelease bile juice.

53. The hormone that stimulates the stomach to secrete gastric juice is

(1) Enterokinase (2) Enterogastrone (3) Gastrin (4) Rennin

Sol. Answer (3)

This hormone is secreted in stomach and stimulates the gastric gland to secrete and release the gastric juice.

54. Cholecystokinin and duocrinin are secreted by

(1) Adrenal cortex (2) Thyroid gland (3) Intestine (4) Pancreas

Sol. Answer (3)

Hormone Source

Cholecystokinin Small intestine

Pancreozymin Small intestine

Duocrinin Duodenum (part of small intestine)

55. Which part of body secretes the hormone secretin?

(1) Stomach (2) Oesophagus (3) Ileum (4) Duodenum

Sol. Answer (4)

Duodenum secretes secretin which decreases the secretion of gastric juice.

56. Which of the following hormones is not secreted by duodenum to inhibit the gastric motility?

(1) GIP (2) Enterogastrone (3) Secretin (4) Enterokinase

Sol. Answer (4)

Enterokinase is not a hormone, it is an enzyme.

57. Which of the following carries glucose from digestive tract to liver?

(1) Pulmonary vein (2) Hepatic artery (3) Hepatic portal vein (4) None of these

Sol. Answer (3)

Hepatic portal vein carries glucose from digestive tract to liver via a hepatic portal circulation.

58. In case of vertebrates lacteals are found in

(1) Oesophagus (2) Ear (3) Small intestine (4) Ischium

Sol. Answer (3)

Lacteals are found in villi of small intestine.



59. The movement of ions against the concentration gradient will be

(1) Active transport (2) Osmosis (3) Diffusion (4) All of these

Sol. Answer (1)

Active transport requires energy (ATP) for the movement of ions against the concentration gradient.

60. Vomiting centre is located in the

(1) Medulla oblongata (2) Stomach and sometimes in duodenum

(3) GI tract (4) Hypothalamus

Sol. Answer (1)

Vomiting centre is located in medulla oblongata.

61. Which one of the following vitamins can be synthesized by bacteria inside the gut?

(1) D (2) A

(3) B1

(4) C

Sol. Answer (3)

Vitamin K and Vitamin B complex are synthesized by bacteria of large intestine (colon).

62. Which one of the following is a protein deficiency disease?

(1) Kwashiorkor (2) Night blindness

(3) Eczema (4) Cirrhosis

Sol. Answer (1)

Kwashiokor → Occurs due to deficiency of protein.

Night blindness → Due to deficiency of vitamin A.

Eczema → Scaliness of skin due to allergy or due to deficiency of Vit. B7.

Cirrhosis → It occurs due to deposition of fibre in liver in alcoholic person.

63. Stool of a person is whitish grey coloured due to malfunction of which of the following organ?

(1) Pancreas (2) Spleen

(3) Kidney (4) Liver

Sol. Answer (4)

The yellow colour of stool is due to stercobilin, which is a breakdown product of bile pigment (bilirubin)

And as liver is responsible for the production of bile juice. If there is malfunctioning of liver, then bile will not

produce and stool of person become whitish grey.

64. Constipation can be prevented or removed by

(1) Taking more roughage (2) Taking purgatives rich in magnesium salt

(3) Taking distilled water (4) Both (1) & (2)

Sol. Answer (4)

Constipation can be prevented by taking more roughage because it is a fibre and retains more water with it

and increase the fluidity.

And constipation is also removed by taking purgatives rich in magnesium salt because it stimulates intestinal

peristalsis and evacuation of fluid faeces.



65. During prolonged fastings, in what sequence are the following organic compounds used up by the body?

(1) First carbohydrates, next fats and lastly proteins (2) First fats, next carbohydrates and lastly proteins

(3) First carbohydrates, next proteins and lastly lipids (4) First proteins, next lipids and lastly carbohydrates

Sol. Answer (1)

Because carbohydrate is readily combustible nutrient for providing energy and then fats will provide us energy

and at last protein will provide energy because protein is actually a body building biomolecule.

66. A moderately active person requires energy per day

(1) 2000 kcal (2) 1000 kcal

(3) 750 kcal (4) 2800 kcal

Sol. Answer (4)

The minimum energy required for routine metabolic rate is 2200 kcal (in female) and 2800 kcal (in male)

SECTION - D


1. A : Gastrectomy causes iron deficiency anaemia.

R : Hydrochloric acid secreted by oxyntic cells converts ferric into ferrous and iron is absorbed as ferrous ions.

Sol. Answer (1)

Gastrectomy is surgical removal of stomach.

2. A : Cholagogues are substances that cause contraction of gall bladder.

R : These substances cause release of CCK-PZ from duodenum.

Sol. Answer (1)

Cholagogues increases the secretion of bile juice.

3. A : Aptyalism patients have higher than normal incidences of dental caries.

R : Aptyalism is caused by the action of parasympathetic nervous system.

Sol. Answer (3)

Aptyalism is a condition in which no saliva is produce, so there will be no lysozyme which has anti-microbial

activity and prevent the person from dental caries.

4. A : In humans, duct of wirsung from pancreas combines with bile duct before opening into duodenum.

R : Blockage in duct of Wirsung will prevent the endocrine function of pancreas.

Sol. Answer (3)

Blockage of duct of Wirsung will prevent exocrine function of pancreas.

5. A : In acute constipation, purgatives containing magnesium salts are generally used.

R : The osmotic effect of Mg2+ in the intestinal lumen prevents water reabsorption from intestine. Mg2+ increases

the solute concentration in the intestinal lumen because Mg2+ is absorbed very slowly.

Sol. Answer (1)

Purgatives are used for the treatment of acute constipation.



6. A : Liver assist in digestion of fat.

R : Hepatic secretion contains bile salts which emulsify fat

Sol. Answer (1)

Liver secretes bile juice.

7. A : Vomiting is the forcible expulsion of the contents of the upper gastrointestinal tract through the mouth.

R : The strongest stimuli for vomiting are irritation and distension of the stomach.

Sol. Answer (2)

Both assertion and reason are true but the reason is not the correct explanation of the assertion.

8. A : Gastric emptying is slowest after a fat-laden meal containing large number of triglycerides.

R : Fatty acids in chyme stimulate release of both CCK and GIP, which slow stomach emptying.

Sol. Answer (1)

GIP (Gastric Inhibitory Peptide) and CCK (Cholecystokinin).

9. A : Trypsin is secreted in pancreatic juice as trypsinogen.

R : Zymogenic forms protect pancreas from autodigestion.

Sol. Answer (1)

Trypsinogen is inactive form of trypsin.

10. A : Trypsin is an example of endopeptidase and is present in the pancreatic juice.

R : Trypsin acts on the interior peptide of a protein molecule.

Sol. Answer (1)

Pepsin, trypsin and chymotrypsin and endopeptidase enzymes.

� � �


Solutions

SECTION - A


(Respiratory Organs)

1. The process of oxidation of glucose during which CO2, H

2O and energy are produced is known as

(1) Breathing (2) Inspiration (3) Respiration (4) Expiration

Sol. Answer (3)

Breathing = Inspiration (Inhalation of air) + Expiration (Exhalation of air)

Respiration is the process of oxidation of food in which CO2, H

2O and energy is/are produced.

2. The respiratory organs vary in different animals due to their

(1) Nutrition (2) Habitat and level of organisation

(3) Excretion (4) Reproduction

Sol. Answer (2)

Because of different habitat (place where an animal live) and level of organisation, the breathing mechanism

varies, hence the respiratory organ also get vary in different animals.

3. Which of the following are the respiratory organs of insects?

(1) Trachea (2) Gills (3) Cuticle (4) Lungs

Sol. Answer (1)

Insect(e.g. Cockroach) → Tracheal system

Gills → Aquatic animal (fish, amphibian)

Cuticle → Earthworm

Lungs → Birds, reptiles, mammals

4. Which animal among the following respires via buccal cavity, moist skin and lungs?

(1) Hydra (2) Frog (3) Sycon (4) Earthworm

Sol. Answer (2)

Frogs can respire by their moist skin, buccal cavity and lungs as they live on land and its larval form i.e.

tadpole which lives in water respire through gills.

Hydra, Sycon : No well-developed respiratory system, exchange of gases by simple diffusion.

Earthworm : Moist cuticle.

Chapter 4

Breathing and Exchange of Gases

74 Breathing and Exchange of Gases Solutions of Assignment


5. Respiratory organs in aquatic arthropods like cray fish, prawn and molluscs like Unio are

(1) Body wall (2) Lungs (3) Trachea (4) Gills

Sol. Answer (4)

Aquatic arthropods (Crustacean) respire through gills.

6. Which of the following has most well-developed respiratory system?

(1) Mammals (2) Invertebrates (3) Amphibians (4) Hemichordates

Sol. Answer (1)

The respiratory system is well developed in the vertebrates as they have more complex body.

In between amphibians and mammals, the mammals have more well-developed respiratory organ i.e., lungs.

7. Which structure in human respiratory system is involved in conditioning of air?

(1) Internal nares (2) Nasal chamber (3) Larynx (4) Trachea

Sol. Answer (2)

(1) Mucus from goblet cells and glands make the surface sticky for trapping dust particles present in inspired

air.

(2) Moisture from the epithilium also makes the air humid.

(3) It brings the temperature of the incoming air, upto the body temperature.

8. A thin-elastic cartilaginous flap which prevents the entry of food into the larynx is known as

(1) Glottis (2) Wind pipe (3) Epiglottis (4) Bronchiole

Sol. Answer (3)

Epiglottis covers the glottis during swallowing of food.

9. At which level of thoracic vertebra, trachea divides

(1) 2nd thoracic vertebra (2) 5th thoracic vertebra (3) 3rd thoracic vertebra (4) 4th thoracic vertebra

Sol. Answer (2)

The trachea divides into right and left primary bronchi at the level of 5th thoracic vertebra.

10. Trachea divides into right and left

(1) Secondary bronchi (2) Tertiary bronchi (3) Bronchioles (4) Primary bronchi

Sol. Answer (4)

The trachea divides into right and left primary bronchi at the level of 5th thoracic vertebra.

11. Which membrane covers the lungs and provide protection?

(1) Pericardium (2) Renal capsule (3) Pleura (4) Epineurium

Sol. Answer (3)

Pericardium : Covers heart

Renal capsule : Covers kidney

Pleura : Lungs

Epineurium : Covers nerve trunk

75Solutions of Assignment Breathing and Exchange of Gases


12. Where are lungs situated in human body?

(1) Abdominal cavity (2) Thoracic cavity (3) Coelomic cavity (4) Pleural cavity

Sol. Answer (2)

A pair of lungs are present in humans, lie in an air-tight chamber known as thoracic cavity or chest cavity.

(Mechanism of Breathing)

13. Which of the following volume is not included in vital capacity

(1) ERV (2) TV (3) IRV (4) RV

Sol. Answer (4)

Because VC = ERV + TV + IRV

or VC = ERV + IC

Here, RV = Residual volume IRV = Inspiratory reserve volume

VC = Vital capacity IC = Inspiratory capacity

ERV = Expiratory reserve volume TV = Tidal volume

14. What is the last step involved in respiration?

(1) Diffusion of gases

(2) Breathing

(3) Utilisation of O2 by body cells and resultant release of CO

2

(4) Transport of gases

Sol. Answer (3)

Steps involve in respiration :

(1) Breathing (2) Diffusion of gases between alveoli and blood

(3) Transport of gases (4) Diffusion of gases between blood and tissue

(5) Utilisation of O2 by body cell

15. Inspiration occurs when intra-pulmonary pressure is

(1) Higher than atmospheric pressure (2) Lower than atmospheric pressure

(3) Equal to atmospheric pressure (4) Zero compared to atmospheric pressure

Sol. Answer (2)

Air can flow to lungs, when the pressure within the lungs is less than the atomospheric pressure.

16. Which muscles help us to increase the strength of inspiration and expiration?

(1) Cardiac muscles (2) Abdominal muscles

(3) Internal intercostal muscles (4) Both (2) & (3)

Sol. Answer (4)

Cardiac muscle i.e., muscle of heart, it do not have any role in inspiration and expiration.

Rest two muscles i.e., abdominal and internal intercostal muscle undergo contraction and increase the strength

of expiration.

17. The breathing rate of a normal healthy man is

(1) 8–18 times/min (2) 6–12 times/min (3) 16–24 times/min (4) 12–16 times/min

Sol. Answer (4)

Breathing rate of a normal healthy man is about 12–16 times/min.



18. What is the value of tidal volume in a normal healthy man?

(1) Approximately 6000–8000 ml/min (2) 1000–1100 ml/min

(3) 2500–3000 ml/min (4) Approximately 8000–12000 ml/min

Sol. Answer (1)

Minute volume = TV × Breathing rate

500 ml × 12–16 /min ⇒ ∼ 6000 – 8000 ml

Minute volume is also known as pulmonary ventilation.

19. The volume of air remaining in the lungs even after a forceful expiration is

(1) Tidal volume (2) Residual volume

(3) Inspiratory reserve volume (4) Expiratory reserve volume

Sol. Answer (2)

(1) Tidal volume (500 ml) : It is the volume of air a person can inspired or expired during normal breathing.

(3) Inspiratory reserve volume (2500 – 3000 ml) : The additional or extra volume of air, a person can expire

by forceful expiration.

(4) Expiratory reserve volume (1000 – 1100 ml) : The additional or extra volume of air, a person can expire

by forceful expiration.

(Exchange of Gases, Transport of Gases)

20. What is the main site of human respiratory system where exchange of gases occurs?

(1) Alveoli (2) Bronchiole

(3) Primary and secondary bronchi (4) Trachea

Sol. Answer (1)

The membrane of alveoli is very thin, irregular and richly supplied with blood vessels. Due to very close contact

of blood vessels with alveoli, the exchange of gases takes place easily.

21. Partial pressure for oxygen and CO2 is represented as

(1) pO and pCO (2)2

O COp and p (3) pO

2 and pCO

2(4) O

2p and CO

2p

Sol. Answer (3)

Gaseous exchange depends on partial pressure of gases.

22. What will be the pO2 and pCO

2 in atmospheric air as compared to alveoli?

(1) High pO2 and low pCO

2(2) High pCO

2 and low pO

2

(3) Both are equal (pCO2 = pO

2) (4) Low pO

2 and low pCO

2

Sol. Answer (1)

In atmospheric air : pO2 = 159 mmHg

pCO2 = 0.3 mmHg

In alveoli : pO2 = 104 mmHg

pCO2 = 40 mmHg

23. What is the value of pCO2 in atmospheric air, alveoli and tissues respectively?

(1) 0.3 mm Hg, 40 mm Hg and 95 mm Hg (2) 95 mm Hg, 40 mm Hg and 159 mm Hg

(3) 45 mm Hg, 0.3 mm Hg and 40 mm Hg (4) 0.3 mm Hg, 40 mm Hg and 45 mm Hg



Sol. Answer (4)

Respiratory gas Atmospheric air Alveoli Blood Blood Tissue(oxygenated) (Deoxygenated)

O 159 104 40 95 40

CO 0.3 40 45 40 45

2

2

24. O2 binds with haemoglobin of RBC to form

(1) Carboxyhaemoglobin (2) Oxyhaemoglobin

(3) Carbaminohaemoglobin (4) Aminohaemoglobin

Sol. Answer (2)

In lungs

2 2In tissue

(Haemoglobin) (Oxygen) (Oxyhaemoglobin)

Hb O HbO+ ��⇀↽��

2 2

(Carbon dioxide) (Carbamino-haemoglobin)

Hb CO HbCO��⇀↽��+

(Carbon monoxide) (Carboxy haemoglobin)

Hb CO HbCO+ ��⇀↽��

25. With which part of Hb, O2 molecules bind?

(1) Haem (2) Globin

(3) Both haem and globin (4) Amino group of globin

Sol. Answer (1)

Because haem group contains Fe2+, which has affinity for oxygen.

26.(1)

2 2(2)Hb + O HbO��⇀

↽��

Select (1) and (2) from the given options

(1) (1) is tissues and (2) is lungs (2) (1) is lungs and (2) is blood

(3) (1) is blood and (2) is lungs (4) (1) is lungs and (2) is tissues

Sol. Answer (4)

Lungs

2 2TissueHb + O HbO��⇀

↽��

27. A graph is plotted between pO2 and percentage saturation of Hb with O

2 is known as

(1) O2 association curve (2) CO

2-O

2 dissociation curve

(3) O2 dissociation curve (4) CO

2-O

2 association curve

Sol. Answer (3)

A graphical representation of relationship between pO2 and percentage saturation of haemoglobin with O

2

is known as oxygen dissociation curve or oxygen haemoglobin dissociation curve. It is sigmoid or S-shaped

curve.



28. Which factors affect the dissociation of O2 from Hb?

(1) pH, pO2, pCO

2 and temperature (2) Only pH

(3) Salinity, temperature and pCO2

(4) HCO3

– ions concentration, pH and salinity

Sol. Answer (1)

Factors responsible for the dissociation of oxygen from Hb which occurs in the body tissues :

(a) Low partial pressure of oxygen (c) High partial pressure of carbon dioxide

(c) Low pH (d) High temperature

29. High percentage of CO2 is transported in dissolved form as compared to O

2. This is because

(1) O2 has high solubility in plasma (2) CO

2 has high solubility in plasma

(3) pCO2 is high in blood than pO

2(4) CO

2 has low solubility in plasma

Sol. Answer (2)

Ratio of CO2 and O

2 solubility in plasma is 25 : 1 (CO

2 : O

2).

30. Which factor in tissues favours the formation of HCO3

– and H+ ions in the blood?

(1) Low pCO2

(2) High pO2

(3) High pCO2

(4) High alkalinity

Sol. Answer (3)

2

Carbonic anhydrase Carbonic anhydrase

2 2 2 3 3(Hydrogen ion)Zn (Carbonic acid) (Bicarbonate ion)

CO H O H CO H HCO+

+ −+ +��⇀ ��⇀↽�� ↽��

31. How much CO2 is delivered to the alveoli by every 100 ml of deoxygenated blood?

(1) 6 ml (2) 4 ml (3) 5 ml (4) 3 ml

Sol. Answer (2)

About 4 ml CO2 is delivered to the alveoli by every 100 ml of deoxygenated blood.

32. Which enzyme is present in RBCs and plasma to catalyse the given reaction?

+

2 2 2 3 3

Carbonic acid

CO +H O H CO H +HCO−

��⇀ ��⇀↽�� ↽��

(1) Carbonic anhydrase (2) Catalase (3) Aldolase (4) Carboxylase

Sol. Answer (1)

Because carbonic anhydrase is present in very high concentration in RBC and in small quantity in plasma.

(Regulation of Respiration, Disorders of Respiratory System)

33. A specialised centre known as respiratory rhythm centre regulates respiration. It is located in

(1) Pons (2) Medulla oblongata (3) Cerebrum (4) Cerebellum

Sol. Answer (2)

Respiratory rhythm centre are present in medulla which regulates the normal rhythm of respiration.

34. Which substances when present in high level can activate the chemosensitive area present adjacent to rhythm

centre?

(1) CO2 and O

2(2) HCO

3

– ions and O2

(3) CO2 and H+ ions (4) H+ and HCO

3

– ions

Sol. Answer (3)

Chemosensitive area i.e. sensitive for chemicals and is located adjacent to the rhythm centre which contains

chemoreceptors which are sensitive for CO2 and H+ ions. The respiratory centre is stimulated by concentration

or partial pressure of CO2 and H+ ions in blood and body fluids.



35. Which of the following is an occupational respiratory disease?

(1) Diphtheria (2) Pneumonia (3) Tuberculosis (4) Asbestosis

Sol. Answer (4)

Occupational respiratory disorders occur due to the continuous exposure to harmful substances, gases, fumes

and dust in the environment, where a person works.

Asbestosis caused due to continuonus exposure to asbestos dust at place of work.

Pneumonia : Caused due to the bacteria like Streptococcus pneumoniae and haemophilus influenzae.

Tuberculosis : Caused due to Mycobacterium tuberculosis.

Diphtheria : Caused due to Cornynebacterium diphtheriae.

SECTION - B


(Respiratory Organs)

1. Which group of animals respire through lungs?

(1) Earthworm and insects (2) Sponges, coelenterates and flatworms

(3) Fishes and aquatic arthropods (4) Reptiles, birds and mammals

Sol. Answer (4)

(i) Earthworm → Respires through moist cuticle

(ii) Insects (Cockroach) → Tracheal system

SpongesCoelenteratesFlatworms

(iii)(iv)(v)

No well-developed respiratory organ is present. Exchange of gases occursby simple diffusion.

FishAquatic arthropod

(vi)(vii)

Gills

ReptilesBirdsMammals

(viii)(ix)(x)

Lungs

2. Skin of man cannot act as respiratory organ because

(1) It is dry (2) It is not thin

(3) It is not permeable to O2 and CO

2(4) All of these

Sol. Answer (4)

Because human skin is dry (does not allow exchange of gases), it is not thin (gases can pass through thin

membrane) and it is impermeable to O2 and CO

2).

3. What is the function of respiratory part of human respiratory system?

(1) It clears the incoming air from foreign particles

(2) It brings the temperature of air upto the body temperature

(3) It transports the atmospheric air

(4) It exchanges O2 and CO

2 between blood and atmospheric air

Sol. Answer (4)

Respiratory part of human respiratory system includes alveoli and their ducts.

It is the main site of human respiratory system where diffusion of gases (O2 and CO

2) occurs.



4. Ventrally and laterally, the thoracic chamber is formed by

(1) Diaphragm and sternum respectively (2) Ribs and sternum respectively

(3) Sternum and ribs respectively (4) Vertebral column and diaphragm respectively

Sol. Answer (3)

Thoracic cavity is formed :

Dorsally – By the vertebral column

Ventrally – By the sterum

Laterally – By the ribs

5. Adam's apple is another name for

(1) Sound box in birds (2) Sound box in man

(3) Epiglottis (4) Thyroid cartilage

Sol. Answer (4)

Its shape is like apple. It is hyaline cartilage and more prominent in male.

6. Ring like cartilage of larynx is known as

(1) Thyroid cartilage (2) Arytenoid cartilage (3) Cricoid cartilage (4) Cartilage of Santorini

Sol. Answer (3)

Cricoid cartilage has signet ring-like structure lie below the thyroid cartilage and it is made up of hyaline

cartilage.

7. Which of the following prevents collapsing of trachea?

(1) Muscles (2) Diaphragm (3) Ribs (4) Cartilaginous rings

Sol. Answer (4)

Trachea is lined by C-shaped cartilagenous ring, which prevents the collapsing of trachea.

8. Number of alveoli in the human lungs has been estimated to be approximately

(1) 100 million (2) 300 million (3) 125 million (4) 300 billion

Sol. Answer (2)

Factual data.

9. In human, oblique fissure is present in

(1) Right lung (2) Left lung (3) Both of these (4) None of these

Sol. Answer (3)

Both right and left lungs have oblique fissure whereas only right lung also has a horizontal fissure.

(Mechanism of Breathing)

10. A pair of external nostrils present in humans opens out

(1) Below the upper lips (2) Above the upper lips

(3) Between upper and lower lips (4) Above the larynx

Sol. Answer (2)



11. During inspiration, the volume of thoracic cavity increases because of

(1) Contraction of diaphragm and external intercostal muscles

(2) Relaxation of diaphragm and external intercostal muscles

(3) Contraction of diaphragm and relaxation of external intercostal muscles

(4) Relaxation of diaphragm and contraction of external intercostal muscles

Sol. Answer (1)

During inspiration, the contraction of diaphragm muscle causes it to become flat and lowered down, thereby

increasing the volume of thoracic cavity in antero-posterior axis.

The contraction of external intercostal muscle, lift ribs and sternum up and outward causing an increase in

volume of thoracic cavity in the dorso-ventral axis i.e., backward-forward direction.

12. Volume of thoracic chamber increases in antero-posterior and dorso-ventral axis in rabbit by

(1) Contraction of diaphragm and external intercostal muscles respectively

(2) Relaxation of diaphragm and external intercostal muscles respectively

(3) Relaxation of diaphragm and abdominal muscles respectively

(4) Contraction of abdominal muscles and relaxation of external intercostal muscles respectively

Sol. Answer (1)

During inspiration, the contraction of diaphragm muscle causes it to become flat and lowered down, thereby

increasing the volume of thoracic cavity in antero-posterior axis.

The contraction of external intercostal muscle, lift ribs and sternum up and outward causing an increases in

volume of thoracic cavity in the dorso-ventral axis i.e., backward-forward direction.

13. Which instrument helps in clinical assessment of pulmonary functions?

(1) Sphygmomanometer (2) Stethoscope (3) Spirometer (4) Electrocardiograph

Sol. Answer (3)

Sphygomomanometer → Use to measure the blood pressure.

Stethoscope → To check the normal rhythm of heart (i.e., to listen normal and abnormal heart sound)

Spirometer → To assess pulmonary function

Electrocardiograph → Instrument use for taking ECG(electrocardiagram)

14. Expiration occurs due to

(1) Relaxation of diaphragm and external intercostal muscle

(2) Contraction of internal intercostal muscles and diaphragm

(3) Relaxation of abdominal and internal intercostal muscles

(4) Contraction of diaphragm and relaxation of abdominal muscles

Sol. Answer (1)

Expiration : It is the moving of air out of lungs if the pressure within the lungs is more than the atmospheric

pressure.

Relaxation of the diaphragm and the external intercostal muscle returns the diaphragm and sternum to their

normal thoracic volume and thereby pulmonary volume.

15. What happens to the volume of pulmonary cavity when there is an increase in the volume of thoracic chamber?

(1) It decreases (2) It increases

(3) It remains same (4) First decreases and then increases



Sol. Answer (2)

Increase in the volume of thoracic cavity

Similar increase in the volume of pulmonary cavity

Decrease in pressure within the pulmonary cavity

Air enters from atmosphere to the lungs as it moves from higher pressure to lower pressure

Leads to

Causes

Causes

16. Diaphragm is a dome-shaped muscular structure which separates

(1) Coelomic cavity from pelvic cavity (2) Pleural cavity from thoracic cavity

(3) Thoracic cavity from abdominal cavity (4) Pelvic cavity from abdominal cavity

Sol. Answer (3)

Thoracic is closed below by the diaphragm which is a dome-shaped structure made up of muscles and

separates thoracic cavity from abdominal cavity (containing most of the digestive organs).

17. What happens when pressure within the pulmonary cavity is higher than the atmospheric pressure?

(1) Inhalation of air (2) Expulsion of air

(3) No inhalation and expulsion of air occurs (4) Lungs inflate and rupture

Sol. Answer (2)

High pressure in pulmonary cavity compared to atmosphere results in explusion of air. Air moves high pressure

to low pressure.

18. An additional volume of air, a person can inspire by a forceful inspiration is known as

(1) Inspiratory capacity (2) Expiratory capacity

(3) Expiratory reserve volume (4) Inspiratory reserve volume

Sol. Answer (4)

IRV is the additional volume of air a person can inspire by a forceful inspiration.

IRV = 2500 – 300 ml

IC = IRV + TV

3000 – 3500 ml

19. Volume of air remains in the lungs after normal expiration is

(1) ERV + RV (2) IRV + RV (3) RV + IRV + ERV (4) TV

Sol. Answer (1)

Volume of air remains in the lungs after normal expiration is known as functional residual capacity (FRC).

FRC = ERV + RV = 2500 ml

20. If a person exhales out forcefully by applying all his efforts. What will the pulmonary volume inhaled by him

immediately under normal condition without applying any extra effort?

(1) TV + IRV (2) TV only (3) TV + ERV (4) TV + IRV + ERV

Sol. Answer (3)

After a normal inspiration, the total volume of air a person can expire is known as expiratory capacity

(EC) = TV + ERV

Exhaled forcefully ⇒ TV goes out, ERV goes out

Normal inspiration ⇒ ERV + TV has to be filled



(Exchange of Gases, Transport of Gases)

21. Solubility of CO2 is ______ times higher than that of O

2

(1) 40 - 45 (2) 20 - 25 (3) 100 - 200 (4) 200 - 300

Sol. Answer (2)

CO2 : O

2 (Solubility of CO

2 : O

2)

25 : 1

22. What are the characteristics of alveoli?

(1) Very thin, irregular walled and highly vascularised (2) Thick and smooth membrane

(3) Network of blood capillaries and thick-walled (4) Thick, regular walled and lack of blood vessels

Sol. Answer (1)

Alveoli membrane is very thin, irregular, richly supplied with blood vessels because of which exchange of gases

easily occurs here.

23. What is the value of pO2 in alveoli and tissues respectively?

(1) 104 mm Hg and 150 mm Hg

(2) 45 mm Hg and 0.3 mm Hg



Sol. Answer (3)

Respiratory gas Atmospheric air Alveoli Blood Blood Tissue(oxygenated) (Deoxygenated)

O 159 104 40 95 40

CO 0.3 40 45 40 45

2

2

24. Which are the three main layers that form the diffusion membrane?

(1) Thin squamous epithelium of alveoli, basement membrane of bronchioles and basement substance

(2) Thin squamous epithelium of alveoli, endothelium of alveolar capillaries and the basement substance

(3) Basement substance, cuboidal epithelium of alveoli and stratified epithelium of bronchiole

(4) Ciliated epithelium of trachea, endothelium of capillaries and basement substance

Sol. Answer (2)

Diffusion of O2 and CO

2 depends on the thickness of diffusion membrane.

25. Which of the following is not a character of respiratory surface?

(1) Thin, permeable to gases (2) Extensive

(3) Least vascular (4) Moist

Sol. Answer (3)

Respiratory surface should be highly vascular for the easy transport of gases or exchange of gases with the

blood.



26. What is the percentage of O2 transported in dissolved form through the plasma?

(1) About 7% (2) About 3% (3) About 20–25% (4) About 15%

Sol. Answer (2)

Oxygen transport by plasma = 3%

Oxygen transport by oxyhaemoglobin = 97%

27. How many O2 molecules can bind with single molecule of Hb?

(1) 8 (2) 6 (3) 4 (4) 4.5

Sol. Answer (3)

Haemoglobin consists of four polypeptide chain (2α and 2β) having heme as prosthetic group. Heme is iron

(Fe2+) containing prophyrin ring. One haemoglobin binds four oxygen molecules, one per heme and form

oxyhemoglobin.

Hb + 4O2 ��⇀↽�� Hb(O

2)4

28. To which part of Hb, CO2 binds?

(1) Haem (2) Amino group of globin

(3) Iron of haem group (4) Carboxy group of globin

Sol. Answer (2)

Haemoglobin = Heme + Globin

Contain Fe with porphyrin ring2+

Include four polypeptide chain ( )α β2 2

CO2 bind to amino group of globin and form carbaminohaemoglobin.

2 2(Haemoglobin) (Carbamino haemoglobin)(Amino group)

Hb CO HbCO+ ��⇀↽��

29. Which of the following condition is not responsible for shifting the curve towards left?

(1) High pO2

(2) Low pCO2

(3) Low temperature (4) High H+ ion concentration

Sol. Answer (4)

Following are the conditions responsible for shifting the curve towards left :

(a) High pO2

(b) Low pCO2

(c) Less H+ concentration and high pH

(d) Low temperature

All above four conditions are favourable for the association of oxygen with hemoglobin, at alveoli.

30. Which factors favour the binding of CO2 with Hb in tissues?

(1) High pCO2 and high pO

2(2) Low pCO

2 and high pO

2

(3) Low pCO2 and low pO

2(4) High pCO

2 and low pO

2



Sol. Answer (4)

Condition favourable for the binding of CO2 with Hb or we can say dissociation of O

2 from Hb are :

(a) Low pO2

(b) High pCO2

(c) More H+ concentration and low pH (d) High temperature

In these conditions, oxygen dissociation curve will shift to right.

31. In mature mammalian erythrocytes, the respiration is

(1) Aerobic (2) Anaerobic

(3) Sometimes aerobic and sometimes anaerobic (4) Absent

Sol. Answer (2)

Mature RBCs do not have cell organelle (like mitochondria) and nucleus, so in mature RBC anaerobic

respiration occurs.

32. The amount of oxygen transported by one litre of blood under strenous condition is approximately

(1) 5 ml (2) 50 ml (3) 15 ml (4) 150 ml

Sol. Answer (4)100 ml of blood contains about 20 ml of O∼

2

In normal physiological condition In strenous/exercise condition

5 ml goes to tissue +

15 ml returned via venous blood→15 ml goes to tissue +

5 ml returned via venous blood→

So, 100 ml of blood transport → 15 ml of O2 (strenous condition)

1000 ml of blood transport → 150 ml of O2

(Regulation of Respiration, Disorders of Respiratory System)

33. Pneumotaxic centre can moderate the functions of respiratory rhythm centre by

(1) Reducing the duration of inspiration

(2) Increasing the duration of inspiration only

(3) First increasing and then reducing the duration of expiration

(4) Increasing the duration of expiration only

Sol. Answer (1)

Pneuomotaxic centre is present in the pons region of hind brain.

It is also known as "switch off point of inspiration" i.e. it reduces the duration of inspiration and alter the

respiratory rate and depth of breathing.

34. A chronic disorder in which alveolar walls are damaged due to excessive cigarette smoking is

(1) Asthma (2) Emphysema (3) Silicosis (4) Bronchitis

Sol. Answer (2)

Emphysema

Due to excessive cigarette smoking

Walls of alveoli get damaged and loss of elasticity of walls of bronchioles and alveoli

Due to which, surface area for exchange of gases is reduced



Asthma : Caused because of allergen and effects the respiratory tract.

Bronchitis : Inflammation of bronchi.

Silicosis : It is an occupational respiratory disorder caused due to continuous exposure of asbestos dust at

place of work.

35. Which of the following is not a symptom of asthma?

(1) Difficulty in breathing (2) Breathing noisily / wheezing

(3) Alveolar walls are damaged (4) Inflammation of bronchi and bronchioles

Sol. Answer (3)

Wall of allevoli gets damaged due to excessive smoking is a symptom of chronic disorder, emphysema.

SECTION - C


1. The partial pressure of oxygen in the alveoli of the lungs is [NEET(Phase-2) 2016]

(1) Equal to that in the blood (2) More than that in the blood

(3) Less than that in the blood (4) Less than that of carbon dioxide

Sol. Answer (2)

Partial pressure of oxygen in alveoli of lungs is 104 mm of Hg that is more than that of blood in pulmonary

artery (40 mm of Hg).

2. Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled

because [NEET(Phase-2) 2016]

(1) There is a negative pressure in the lungs

(2) There is a negative intrapleural pressure pulling at the lung walls

(3) There is a positive intrapleural pressure

(4) Pressure in the lungs is higher than the atmospheric pressure

Sol. Answer (2)

Lungs do not collapse between breaths and some air always remains in the lung which can never be expelled

because there is a negative intrapleural pressure pulling at the lung walls.

3. Name the chronic respiratory disorder caused mainly by cigarette smoking [NEET-2016]

(1) Respiratory alkalosis (2) Emphysema (3) Asthma (4) Respiratory acidosis

Sol. Answer (2)

Emphysema is characterised by inflation of alveoli which is mainly due to chronic cigarette smoking.

4. Reduction in pH of blood will [NEET-2016]

(1) Release bicarbonate ions by the liver

(2) Reduce the rate of heart beat

(3) Reduce the blood supply to the brain

(4) Decrease the affinity of hemoglobin with oxygen

Sol. Answer (4)

Reduction in pH of blood favours the dissociation of oxyhemoglobin.

5. Asthma may be attributed to [NEET-2016]

(1) Accumulation of fluid in the lungs (2) Bacterial infection of the lungs

(3) Allergic reaction of the mast cells in the lungs (4) Inflammation of the trachea



Sol. Answer (3)

Asthma is an allergic reaction characterised by spasm of bronchi muscles because of effect of histamine

released by mast cells.

6. When you hold your breath, which of the following gas changes in blood would first lead to the urge to breathe?

[AIPMT-2015]

(1) Rising CO2 and falling O

2 concentration (2) Falling O

2 concentration

(3) Rising CO2 concentration (4) Falling CO

2 concentration

Sol. Answer (3)

7. Approximately seventy percent of carbon-dioxide absorbed by the blood will be transported to the lungs

[AIPMT-2014]

(1) As bicarbonate ions (2) In the form of dissolved gas molecules

(3) By binding to R.B.C (4) As carbamino - haemoglobin

Sol. Answer (1)

Nearly 20 – 25 percent of CO2 is transported by RBCs, whereas, 70 percent of it is carried as bicarbonates.

About 7 percent of CO2 is carried as dissolved state in plasma.

8. The figure shows a diagrammatic view of human respiratory system with labels A, B, C, and D. Select the

option which gives correct identification and main function and/or characteristic. [NEET-2013]

Lung

Heart

D

Cut end of rib

Bronchus

B

C

A

(1) B-pleural membrane-surround ribs on both sides to provide cushion against rubbing

(2) C-Alveoli-thin walled vascular bag like structures for exchange of gases

(3) D-lower end of lungs-diaphragm pulls it down during inspiration

(4) A-trachea-long tube supported by complete cartilaginous rings for conducting inspired air

Sol. Answer (2)

9. Which one of the following is the correct statement for respiration in humans? [AIPMT (Prelims)-2012]

(1) About 90% of carbon dioxide (CO2) is carried by haemoglobin as carbamino-haemoglobin

(2) Cigarette smoking may lead to inflammation of bronchi

(3) Neural signals from pneumotoxic centre in pons region of brain can increase the duration of inspiration

(4) Workers in grinding and stone-breaking industries may suffer, from lung fibrosis

Sol. Answer (4)

Option (1) is wrong, because ~70% of CO2 is carried by haemoglobin as carbaminohaemoglobin.

Option (2) is wrong, because cigarette smoking lead to damage of alveoli wall.

Option (3) is wrong, because pneumotaxic centre in pons region of brain decrease the duration of inspiration.



10. People who have migrated from the planes to an area adjoining Rohtang Pass about six months back


(1) Have the usual RBC count but their haemoglobin has very high binding affinity to O2

(2) Have more RBCs and their haemoglobin has a lower binding affinity of O2

(3) Are not physically fit to play games like football

(4) Suffer from altitude sickness with symptoms like nausea, fatigue, etc

Sol. Answer (2)

High altitude (pO2

less) so more RBC production, which leads to polycythemia i.e., increased RBC count.

11. A large proportion of oxygen is left unused in the human blood even after its uptake by the body tissues.

This O2


(1) Helps in releasing more O2 to the epithelial tissues

(2) Acts as a reserve during muscular exercise

(3) Raises the pCO2 of blood to 75 mm of Hg.

(4) Is enough to keep oxyhaemoglobin saturation at 96%

Sol. Answer (2)

Because during exercise, contraction of muscle occurs and for that more energy is required and for energy

oxygen is required.

12. The figure given below shows a small part of human lung where exchange of gases takes place. In which

one of the options given below, the one part A, B, C or D is correctly identified along with its function.


D

B

A

C

Option:

(1) B: Red blood cell – transport of CO2 mainly.

(2) C: Arterial capillary – passes oxygen to tissues

(3) A: Alveolar cavity – main site of exchange of respiratory gases

(4) D: Capillary wall – exchange of O2

and CO2 takes place here.

Sol. Answer (3)

Option (1) is wrong because RBCs are involved in transport of CO2 and O

2 both

Option (2) is wrong because C is blood capillary.

Option (4) is wrong because D is basement membrane - substance

13. Bulk of carbon dioxide (CO2) released from body tissues into the blood is present as [AIPMT (Mains)-2011]

(1) 70% carbamino-haemoglobin and 30% as bicarbonate

(2) Carbamino-haemoglobin in RBCs

(3) Bicarbonate in blood plasma and RBCs

(4) Free CO2 in blood plasma



Sol. Answer (3)

CO2 transport via plasma 7%

Bicarbonate = 70% (Major)

Haemoglobin = 20–25%

14. Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?


(1) One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs

at all

(2) The lungs can be made fully empty by forcefully breathing out all air from them

(3) One can breathe out air totally without oxygen

(4) One can breathe out air through eustachian tubes by closing both the nose and the mouth

Sol. Answer (1)

If we push voluntarily abdominal contents towards diaphragm, it will lead to expiration without involvement of

intercostal muscle.

15. Which two of the following changes (a–d) usually tend to occur in the plain dwellers when they move to high

altitudes (3,500 m or more)?

(a) Increase in red blood cell size

(b) Increase in red blood cell production

(c) Increased breathing rate

(d) Increase in thrombocyte count

Changes occurring are [AIPMT (Prelims)-2010]

(1) (a) and (b) (2) (b) and (c) (3) (c) and (d) (4) (a) and (d)

Sol. Answer (2)

16. Listed below are four respiratory capacities (a - d) and four jumbled respiratory volumes of a normal human

adult: Respiratory capacities and volumes

(a) Residual volume 2500 mL

(b) Vital capacity 3500 mL

(c) Inspiratory reserve volume 1200 mL

(d) Inspiratory capacity 4500 mL

Which one of the following is the correct matching of two capacities and volumes? [AIPMT (Prelims)-2010)]

(1) (a) 4500 mL, (b) 3500 mL

(2) (b) 2500 mL, (c) 4500 mL

(3) (c) 1200 mL, (d) 2500 mL

(4) (d) 3500 mL, (a) 1200 mL

Sol. Answer (4)

Residual volume – 1200 ml

Vital capacity – 4500 ml

Inspiratory reserve volume – 2500 ml

Inspiratory capacity – 3500 ml



17. What is vital capacity of our lungs? [AIPMT (Prelims)-2008]

(1) Total lungs capacity minus residual volume

(2) Inspiratory reserve volume plus tidal volume

(3) Total lungs capacity minus expiratory reserve volume

(4) Inspiratory reserve volume plus expiratory reserve volume

Sol. Answer (1)

Vital capacity is the maximum volume of air a person can breathe in after a forceful expiration.

Vital capacity (VC) = Total lung capacity – Residual volume

18. Increased asthamatic attacks in certain seasons are related to [AIPMT (Prelims)-2007]

(1) Low temperature (2) Hot and humid environment

(3) Eating fruits preserved in tin containers (4) Inhalation of seasonal pollen

Sol. Answer (4)

19. People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at

an altitude of 5400 metres have around 8 million. This is because at high altitude [AIPMT (Prelims)-2006]

(1) People get pollution-free air to breathe and more oxygen is available

(2) Atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O

2 to

survive

(3) There is more UV radiation which enhances RBC production

(4) People eat more nutritive food, therefore more RBCs are formed

Sol. Answer (2)

20. Which one of the following statements is incorrect? [AIPMT (Prelims)-2006]

(1) The residual air in lungs slightly decreases the efficiency of respiration in mammals

(2) The presence of non-respiratory air sacs, increases the efficiency of respiration in birds

(3) In insects, circulating body fluids serve to distribute oxygen to tissues

(4) The principle of countercurrent flow facilitates efficient respiration in gills of fishes

Sol. Answer (3)

In insects tracheal system serve to distribute oxygen to tissues. Openings of trachae are called spiracles

and present for entry and exist of gases.

21. The majority of carbon dioxide produced by our body cells is transported to the lungs


(1) Dissolved in the blood (2) As bicarbonates

(3) As carbonates (4) Attached to haemoglobin

Sol. Answer (2)

22. In man and other mammals, air passes from outside into the lungs through

(1) Nasal cavity, larynx, pharynx, trachea, bronchi, alveoli

(2) Nasal cavity, larynx, pharynx, trachea, bronchioles, alveoli

(3) Nasal cavity, pharynx, larynx, trachea, bronchioles, bronchi, alveoli

(4) Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli



Sol. Answer (4)

External nostils

Nasal chamber

Internal nares

Nasopharynx

Larynx

Trachea

Bronchi

Bronchioles

Alveolar duct

Alveoli

Respiratory passage :

Conducting part

Respiratory/Exchange part

23. Lungs are enclosed in

(1) Peritoneum (2) Perichondrium

(3) Pericardium (4) Pleural membranes

Sol. Answer (4)

Lungs are enclosed in pleural membranes. i.e. external pleura and internal pleura and in between pleural fluid

is present.

Pericardium → Membrane covers the heart Perichondrium → Outer covering of cartilage

Peritoneum → Covering of visceral organ

24. When a person breathes air through a tube directly into the trachea (tracheotomy) it may lead to serious lung

crushing and infection due to

(1) Cooling effect (2) Drying effect

(3) Non filtering effect (4) All of these

Sol. Answer (4)

Because upper respiratory tract helps in filtering the air, bringing air to body temperature and making it moist.

25. Pitch of the voice is lower in males than females as the vocal cords of man are

(1) Thicker and longer (2) Thinner and longer

(3) Thicker and shorter (4) Thinner and shorter

Sol. Answer (1)

In males, vocal cord is thicker and longer than females and pitch is affected by this

Male → Low pitch and female → High pitch

26. Which of the following statement is not true for man?

(1) Forceful expiration is an active process

(2) Mammals have negative pressure breathing

(3) Internal intercostal and abdominal muscles are muscles of forceful inspiration

(4) Respiration excretes CO2, water etc.



Sol. Answer (3)

Internal intercostal muscle

Abdominal muscle

Muscles of forceful expiration

27. The ventilation movements of the lungs in mammals are governed by

(1) Muscular walls of lung (2) Diaphragm

(3) Costal muscles (4) Both (2) & (3)

Sol. Answer (4)

Inspiration and expiration both governed by diaphragm and costal muscles.

28. In lungs, the air is separated from the venous blood through

(1) Transitional epithelium of alveoli + squamous epithelium of blood vessel

(2) Squamous epithelium of alveoli + endothelium of blood vessel

(3) Squamous epithelium of alveoli + cubical epithelium of blood vessel

(4) Cubical epithelium of alveoli + columnar epithelium of blood vessel

Sol. Answer (2)

Alveolar-capillary membrane or respiratory membrane or diffusion membrane, made up of

(1) Thin squamous epithelium of alveoli

(2) Basement membrane

(3) Endothelial lining of alveolar capillary/blood vessel

29. Which of the following volume or capacity of lungs can’t be measured directly by the spirometer?

(1) Residual volume (2) Functional residual capacity

(3) Total capacity (4) All of these

Sol. Answer (4)

Spirometer can measure the volume of air goes inside and outside the lungs. It does not measure the residual

volume of air that remains inside the lungs. So, residual volume, functional residual capacity and total capacity

cannot be measured by spirometer.

30. Amount of air left in the lung after normal expiration is

(1) Residual volume (2) Inspiratory reserve volume

(3) Expiratory reserve volume (4) Functional residual capacity

Sol. Answer (4)

It is the volume of air left in the lung after normal expiration.

FRC = ERV + RV = 2500 ml

31. Minute Volume of Respiration (MVR) in a person can be defined as

(1) Tidal volume × Breathing rate

(2) (Tidal volume – Anatomic dead space) × Breathing rate

(3) Vital capacity ÷ Breathing rate

(4) Vital capacity ÷ Tidal volume



Sol. Answer (1)

Minute volume is the volume of air a person can inhale per minute.

Minute volume = Tidal volume × Breathing rate

500 ml × 12–16/min

= 6000 - 8000 ml/min

32. When CO2 concentration in blood increases, breathing becomes

(1) Shallower and slow (2) There is no effect on breathing

(3) Slow and deep (4) Faster and deeper

Sol. Answer (4)

Like exercise, when [CO2] increases in blood and [O

2] decreases in blood, then breathing become faster and

deeper.

33. The CO2 content by volume, in the atmospheric air is about

(1) 3.34% (2) 4% (3) 0.0314% (4) 0.34%

Sol. Answer (3)

Air composition :

Nitrogen = 78%

Oxygen = 21%

CO2 = 0.03%

Argon = <1%

Other gases = <1%

34. Although much CO2 is carried in blood, yet blood does not become acidic, because

(1) CO2 is continuously diffused through the tissues and is not allowed to accumulate

(2) In CO2 transport, blood buffers play an important role

(3) CO2 is absorbed by the leucocytes

(4) CO2 combines with water to form H

2CO

3 which is neutralized by NaCO

3

Sol. Answer (2)

Because blood acts as a buffer, which resists the change in pH of blood, because of bicarbonate ions.

35. The carbon dioxide is transported via blood to lungs

(1) In combination with haemoglobin only (2) Dissolved in blood plasma only

(3) In the form of carbonic acid only (4) As carbaminohaemoglobin and as bicarbonates

Sol. Answer (4)

CO2 transport via plasma = 7%; Bicarbonate = 70%; Haemoglobin = 20–25%

36. How does the transport of O2 and CO

2 by blood occur?

(1) With the help of WBCs and blood serum (2) With the help of platelets and corpuscles

(3) With the help of RBCs and blood plasma (4) With the help of RBCs and WBCs

Sol. Answer (3)

Blood is the medium of transport for O2 and CO

2.



37. Blood analysis of a patient reveals an unusually high quantity of carboxyhaemoglobin content. The patient has

been inhaling polluted air containing unusually high content of

(1) Carbon disulphide (2) Chloroform

(3) Carbon dioxide (4) Carbon monoxide

Sol. Answer (4)

2 2(Carbon dioxide) (Carbaminohaemoglobin)

CO Hb HbCO+ ��⇀↽��

(Carbonmonoxide) (Carboxyhaemoglobin)CO Hb HbCO+ ��⇀

↽��

38. What is true about RBCs in humans?

(1) They do not carry CO2 at all

(2) They carry both CO2 and O

2

(3) They transport 99.5 percent of O2

(4) They transport about 80 percent oxygen only and the rest 20 percent of it is transported in dissolved state

in blood plasma

Sol. Answer (2)

RBCs carry 20-25% of CO2 as carbaminohaemoglobin and 97% of O

2 as oxyhaemoglobin.

39. How carbon monoxide, emitted by automobiles, prevents transport of oxygen to the body tissues?

(1) By forming a stable compound with haemoglobin

(2) By inhibiting exchange of O2 at alveoli

(3) By changing oxygen into carbon dioxide

(4) By destroying the haemoglobin

Sol. Answer (1)

Because carbon monoxide has more affinity to bind with haeme group of haemoglobin, than oxygen

250 : 1

CO : O2

40. The respiratory centre, which regulates respiration, is located in

(1) Cerebellum (2) Medulla oblongata

(3) Cerebral peduncle (4) The vagus nerve

Sol. Answer (2)

Respiratory centre is located in medulla oblongata.

41. Mark the incorrect statement

(1) Hering Breuer’s reflex prevents the over expansion of lungs

(2) Oxygen dissociation curve for foetal haemoglobin is on the left side with respect to maternal haemoglobin

(3) When pneumotaxic centre transmits strong signals then inspiration time becomes shorter

(4) Amount of air left in the lung after normal expiration is termed as residual volume only



Sol. Answer (4)

Amount of air left in the lung after forceful expiration is termed as residual volume.

42. Which of the following reflex is involved to prevent excessive inflation of the lungs?

(1) Stretch reflex (2) Hering-Breuer’s reflex

(3) Withdrawal reflex (4) Conditioned reflex

Sol. Answer (2)

Excessive inflation → Stretch receptors get activated → Cause expiration by sending signal through vagus

nerve to inhibit inspiratory area.

43. Chemoreceptors present in carotid and aortic arch are very much sensitive to

(1) Increase in pCO2 in arterial blood

(2) Increase in pO2 in arterial blood

(3) Decrease in pO2 in venous blood

(4) Both (2) & (3)

Sol. Answer (1)

Chemoreceptors present in carotid and aortic are sensitive to CO2 and H+.

44. A person remaining at high altitudes for years becomes more and more acclimatized to the low pO2 by the

following except

(1) Increased pulmonary ventilation

(2) Increased in RBCs and haemoglobin concentration

(3) Polycythemia

(4) Increased cardiac output permanently

Sol. Answer (4)

At high altitude (less pO2) then more RBC production which leads to increase RBC count (polycythemia) in

blood, due which viscosity of blood increases, hence cardiac output decreases.

45. If the blood does not deliver adequate O2 to the tissues, it is called

(1) Anaemia (2) Anorexia

(3) Hypoxia (4) Hypopnea

Sol. Answer (3)

Anorexia – Loss of apetite

Hypoxia – Low oxygen condition in tissue

Hypopnea – Slow breathing

Anaemia – Low hemoglobin, immature RBC

46. Less oxygen due to high levels of carbon dioxide is called

(1) Carbon monoxide poisoning (2) Asphyxia

(3) Dyspnea (4) Apnoea



Sol. Answer (2)

Dyspnea – Painful breathing

Apnoea – No breathing

Asphyxia – Combination of Hypoxia (low O2) + Hypercapnia (more CO

2)

47. Which of the following is not pollution related disorder?

(1) Silicosis (2) Pneumoconiosis

(3) Fluorosis (4) Leprosy

Sol. Answer (4)

Leprosy is caused by Mycobacterium leprae.

48. Hiccups can be best described as

(1) Forceful sudden expiration

(2) Jerky incomplete inspiration

(3) Vibration of the soft palate during breathing

(4) Sign of indigestion

Sol. Answer (2)

Because hiccups occur due to spasm of phrenic muscle which leads to jerky inspiration.

49. Number of alveoli in the human lungs has been estimated to be approximately

(1) 100 million (2) 300 million3

(3) 125 million (4) 300 billion

Sol. Answer (2)

50. Which of the following can be termed as opposite of Bohr’s effect?

(1) Haldane’s effect

(2) Hamburger's phenomenon

(3) Hering - breuer reflex

(4) None of these

Sol. Answer (1)

Haldane's effect and Bohr effect complement each other. In the tissue, addition of CO2 to the blood facilitates

unloading of O2 by Bohr effect. In turn, O

2 unloading favours uptake of CO

2 by Haldane'e effect.

SECTION - D


1. A : Pneumotaxic centre controls rate of respiration.

R : Primarily it controls switch off point of inspiration.

Sol. Answer (1)

Pneumotaxic centre are switch off centre of inspiration.



2. A : Asthmatic patients use bronchiodilator drugs as well as inhalers for symptomatic relief.

R : Asthma is characterized by the spasm of smooth muscles in the wall of bronchioles due to allergen.

Sol. Answer (1)

Asthma is an allergic reaction.

3. A : Major part of carbondioxide is transported in the form of sodium bicarbonate.

R : 0.3 ml of carbon dioxide is transported per 100 ml of blood in dissolved state in plasma of blood.

Sol. Answer (2)

Only 7% of CO2 is transported in dissolved state in plasma of blood.

4. A : In cockroach, inspiration is a passive process.

R : Expansion of abdominal cavity allows the space of expansion of tracheal trunk, as a result air enters

through spiracle.

Sol. Answer (1)

In cockroach, inspiration is a passive process.

5. A : Diffusion of carbondioxide is 20 times faster than oxygen.

R : It is due to difference in partial pressure as well as solubility of diffusing gases.

Sol. Answer (1)

Solubility of CO2 is 20 times faster than O

2.

6. A : The passage starting with the external nostrils upto the terminal bronchiole constitute the respiratory part.

R : The respiratory part transport the air to the alveoli, clears it from the foreign material, humidified and brings

the air to body temperature.

Sol. Answer (4)

The passage starting with the external nostils upto the terminal bronchiole constitute the conducting part.

7. A : Normal expiration during quiet breathing, unlike inspiration, is a passive process because no muscular

contractions are involved.

R : Normal expiration results from the elastic recoil of the chest wall and lungs.

Sol. Answer (1)

Normal expiration in human is due to relaxation of muscles.

8. A : Human blood always contains more amount of CO2 than blood oxygen.

R : Solubility coefficient of CO2 is more than O

2.

Sol. Answer (1)

In 100 ml oxygenated blood, amount of O2 is about 20 ml while of CO

2 is about 48 ml.

9. A : When a person starts doing exercise, rate and depth of breathing increase even before these are changes

in pO2, pCO

2 or H+ concentration.

R : The main stimulus for these quick changes is due to input from the proprioreceptors, which monitor

movements of joints and muscles.

Sol. Answer (1)



10. A : Emphysema is a chronic obstructive disease of lung, causing irreversible distension and loss of elasticity

of alveoli.

R : Emphysema is preventable if chronic exposure to smoke (cigarette and others) and pollutants is avoided.

Sol. Answer (2)

Emphysema is due to inflation of alveoli.

11. A : 100 ml of venous blood has 14.4 ml of O2 i.e., it is still 75% saturated with oxygen in normal condition.

R : About 4.6 ml of O2, i.e. 25% diffuses from arterial blood into the tissue during exercise.

Sol. Answer (3)

Because during normal condition, oxygen demand in tissue is low.

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Solutions

SECTION - A


(Blood and Lymph)

1. Fluid exuding from the clotted blood is

(1) Plasma with most of the formed elements

(2) Plasma without clotting factors

(3) Serum

(4) Both (2) & (3)

Sol. Answer (4)

Fluid exuding from clotted blood is serum i.e., plasma without clotting factor, as all the formed element get

trap there in clot.

2. A reduction in the number of blood platelets is called

(1) Thrombocytopenia

(2) Hemophilia

(3) Anaemia

(4) Hypertension

Sol. Answer (1)

Thrombocytopenia : A reduction in the number of platelets is called thrombocytopenia, which leads to

excessive loss of blood from the body.

Hypertension : High blood pressure.

Anaemia : Low haemoglobin, immature RBC.

Haemophilia is a hereditary genetic disorders that impair the body's ability to control blood clotting, which

is used to stop bleeding after any injury.

Chapter 5

Body Fluids and Circulation

2 Body Fluids and Circulation Solutions of Assignment


3. Each haemoglobin molecule has

(1) One heme group (2) Two heme groups (3) Three heme groups (4) Four heme groups

Sol. Answer (4)

Haemoglobin consists of four polypeptide chain (2α and 2β chains) and 4 heme group.

4. In adults, erythropoiesis occurs in

(1) Liver (2) Red bone marrow (3) Spleen (4) Yellow bone marrow

Sol. Answer (2)

The formation of RBC is known as erythropoiesis and it occurs in the red bone marrow in adults.

5. Granulocytes are formed in

(1) Thymus (2) Bone marrow (3) Kidney (4) Liver

Sol. Answer (2)

Granulocytes are basically a type of leucocytes and formation of leucocyte i.e. leucopoiesis occurs in bone

marrow.

6. Immunity is provided by

(1) Erythrocytes (2) Lymphocytes (3) Megakaryocytes (4) Thrombocytes

Sol. Answer (2)

Lymphocytes are agranulocytes WBC, which exist in two forms i.e., B-lymphocyte and T-lymphocytes and

these are responsible for immune response of the body.

Erythrocytes : These are also known as RBC, which help in gaseous transportation i.e., O2 and CO

2.

Thrombocytes : These are also called platelets and are formed from the megakaryocytes (large cells of bone

marrow).

7. Diapedesis is the characteristic feature of

(1) Monocytes (2) B-lymphocytes (3) T-lymphocytes (4) All of these

Sol. Answer (1)

Monocyte and neutrophil cells undergo diapedesis.

8. Which of the following are phagocytic in nature?

(1) Monocytes (2) Macrophages (3) Neutrophils (4) All of these

Sol. Answer (4)

Monocytes, macrophages and neutrophils are phagocytic in nature because these cells can engulf the foreign

structure like bacteria.

9. ______ are cell fragments rather than true cells.

(1) Erythrocytes (2) Granulocytes (3) Thrombocytes (4) Agranulocytes

Sol. Answer (3)

Thrombocytes i.e. platelets are small, colourless, enucleated fragment of megakaryocytes.

3Solutions of Assignment Body Fluids and Circulation


10. Which of the following formed element activates the plasma clotting factors?

(1) Erythrocytes (2) Monocytes (3) Lymphocytes (4) Thrombocytes

Sol. Answer (4)

Blood platelets on disintegration produce thromboplastin (platelet factor 3), which start the chain of clotting

reactions.

11. Blood group AB has

(1) No antigen (2) No antibody

(3) Neither antigen nor antibody (4) Both antigen and antibody

Sol. Answer (2)

Person with AB blood group have both antigen A and antigen B, but do not have any antibodies.

AB blood also called universal recipient.

12. In ABO system of blood grouping, transfusion is not possible from

(1) A to AB (2) B to AB (3) O to O (4) A to O

Sol. Answer (4)

Because blood group 'O' is universal donor but can accept blood from 'O' blood group person.

13. Erythroblastosis foetalis can occur if

(1) Mother is Rh-ve and foetus is Rh+ve (2) Both mother and foetus are Rh–ve

(3) Mother is Rh+ve and foetus is Rh–ve (4) Both mother and foetus are Rh+ve

Sol. Answer (1)

Mother(Rh –ve)

Father(Rh +ve)

(Rh ) I child (Normal)+ st

(Rh ) II child (Erythroblastosis foetalis)+ nd

If father is Rh+ and mother is Rh–, the foetus can be Rh– or Rh+. This occurs when mother is Rh– and foetus

is Rh+. This is a serious problem. If the Rh– blood of mother has not earlier come in contact with Rh+ blood

through transfusion, her first child does not suffer. But in the subsequent Rh+ foetuses, the antibodies against

Rh antigen of the mother's blood destroy the foetal RBC. This results in erythroblastosis foetalis.

14. Blood platelets release

(1) Fibrinogens (2) Prothrombins (3) Hemoglobin (4) Thromboplastins

Sol. Answer (4)

Blood platelets on disintegration release thromboplastin (platelets factor 3) which starts the chain of blood

clotting reaction.



15. Prothrombin that helps in clotting of blood, is present in

(1) Blood plasma

(2) Blood corpuscles

(3) Blood platelets

(4) Serum

Sol. Answer (1)

Prothrombin is an inactive plasma protein, which helps in clotting of blood.

16. Prothrombin is a

(1) Protein (2) Lipid (3) Nucleotide (4) Carbohydrate

Sol. Answer (1)

Prothrombin is an inactive plasma protein, which helps in clotting of blood.

17. Which of the following prevent(s) blood clotting in uninjured blood vessels?

(1) Albumins (2) Histamine (3) Heparin (4) Globulins

Sol. Answer (3)

Because heparin is an anticoagulant which prevents clotting of blood.

18. Lymph ultimately release the absorbed substances into

(1) Lymphatic capillaries (2) Blood stream (veins)

(3) Lymph node (4) Lymphatic duct

Sol. Answer (2)

Lymph transports oxygen, nutrients, hormones etc. to the body cells and bring CO2 and other metabolic

wastes from the body cells and finally pours the same into the venous system (major vein).

19. Human heart is derived from

(1) Ectoderm

(2) Mesoderm

(3) Endoderm

(4) Both (1) & (3)

Sol. Answer (2)

Because the origin of all muscle except ciliary muscle, has mesodermal origin.

(Circulatory Pathways)

20. Mixing of oxygenated and deoxygenated blood occurs in the heart of

(1) Bird (2) Crocodile (3) Rabbit (4) Frog

Sol. Answer (4)

Because frog has three-chambered heart with two atria and a single ventricle. In frogs, both oxygenated and

deoxygenated blood get mixed up in the single ventricle and the heart pumps out mixed blood. This is known

as incomplete double circulation.



21. How many cardiac cycles are performed per minute in humans?

(1) 1 (2) 12 (3) 27 (4) 72

Sol. Answer (4)

Our heart beats 72 times per minute i.e., 72 cardiac cycles are performed per minute and one cardiac cycle

would occur in 0.8 second.

22. In humans, the volume of blood pumped out by each ventricle per minute is

(1) 1040 mL

(2) 5 L

(3) 2.5 L

(4) 1290 mL

Sol. Answer (2)

During a cardiac cycle, each ventricle pumps out approximately 70 mL of blood. (stroke volume)

Cardiac output = Stroke volume × Number of beats per minute

= 70 mL × 72 ⇒ 5040 mL/min ~ 5 L/min

23. Oxygenated blood from the left ventricle enters into

(1) Pulmonary artery

(2) Aorta

(3) Superior vena cava

(4) Pulmonary trunk

Sol. Answer (2)

LARA

RV LVAorta

Body parts

Lungs

Pulmonary artery

Vena cava

Heart

Pulmonary veinLA = Left atriumLV = Left ventricleRA = Right atriumRV = Right ventricle

24. Contraction of right ventricle pumps blood into

(1) Pulmonary vein (2) Pulmonary artery (3) Coronary sinus (4) Coronary artery

Sol. Answer (2)

LARA

RV LVAorta(Oxygenated blood)Body parts

Lungs

Pulmonary artery

Vena cava /Coronary sinus

Heart

Pulmonary vein(oxygenated blood)

LA = Left atriumLV = Left ventricleRA = Right atriumRV = Right ventricle



(Double circulation)

25. How many double circulations are normally completed by human heart in one minute?

(1) Eight (2) Sixteen (3) Thirty six (4) Seventy two

Sol. Answer (4)

Our heart normally beats 72 times per minute and in every beat the blood passes through the heart twice,

which includes pulmonary and systemic circulation.

26. Systemic circulation of oxygenated blood starts from

(1) Right atrium (2) Left atrium (3) Left ventricle (4) Right ventricle

Sol. Answer (3)

In pulmonary circulation, blood flows from right ventricle to left atrium.

In systemic circulation, blood flows from left ventricle to right atrium.

27. Amino acids are transported from the intestine to liver by

(1) Hepatic artery (2) Hepatic portal vein (3) Pulmonary vein (4) Hepatic vein

Sol. Answer (2)

Hepatic artery carries oxygenated blood to the liver.

Hepatic vein carries deoxygenated blood from the liver to heart.

Hepatic portal vein carries blood from digestive system to liver.

28. Coronary sinus carries _____ to the right atrium.

(1) Interstitial fluid (2) Deoxygenated blood (3) Lymph (4) Oxygenated blood

Sol. Answer (2)

Pulmonary artery(Deoxygenated blood)

LARA

RV LVAorta(oxygenated blood)Body parts

Lungs

Vena cava andCoronary sinus(Deoxygenated blood)

Pulmonary vein(Oxygenated blood)

LA = Left atriumLV = Left ventricleRA = Right atriumRV = Right ventricle

29. The walls of capillaries are composed of endothelium which is

(1) Cuboidal epithelium (2) Squamous epithelium (3) Columnar epithelium (4) Stratified epithelium

Sol. Answer (2)

The walls of capillaries are composed of just one cell layer – a simple squamous epithelium or

endothelium, which permits a more rapid exchange of materials between the blood and tissues.

30. Tunica externa is composed of

(1) Endothelium (2) Connective tissue (3) Smooth muscles (4) Glycoproteins

Sol. Answer (2)

Tunica externa is the outermost layer of artery and vein wall and is composed of connective tissue.



31. Which one of the following represents pulmonary circulation?

(1) Left atrium → Lungs → Right atrium (2) Left atrium → Lungs → Right ventricle

(3) Right ventricle → Lungs → Left ventricle (4) Right ventricle → Lungs → Left atrium

Sol. Answer (4)

In pulmonary circulation, blood flows from right ventricle to lungs then to left atrium.

In systemic circulation, blood flows from left ventricle to body parts then to right atrium.

(Regulation of Cardiac Activity)

32. A special neural centre that can moderate the cardiac function is located in

(1) Cerebrum (2) Pons (3) Medulla oblongata (4) Cerebellum

Sol. Answer (3)

Cardiac rhythm centres are located in medulla oblongata.

SECTION - B


(Blood)

1. T-lymphocytes mature in

(1) Bone marrow (2) Lymph nodes

(3) Bursa of fabricius (4) Thymus

Sol. Answer (4)

Thymus is the primary lymphoid organ where maturation of T lymphocytes takes place.

B cell maturation occurs in bone marrow.

2. The granulocyte to arrive first at the site of an infection is

(1) Neutrophil (2) Eosinophil

(3) Basophil (4) All of these

Sol. Answer (1)

Neutrophils : They are the most abundant leucocytes (60–65%), which have phagocytic nature i.e., they

engulf the harmful germ.

Eosinophils (2–3% of total leucocytes) : They are non-phagocytic and their number increases in people with

allergic condition such as asthma or hay fever.

Basophils (0–1% of total leucocytes (least)) : They release heparin, serotonin and histamine.

3. A person with blood group O will have _____ antibody/antibodies in plasma.

(1) anti-B (2) anti-A

(3) nil (4) anti-A and anti-B

Sol. Answer (4)

O group (universal donor) cannot receive A and B blood because anti-A and anti-B antibodies.



4. Clotting of blood involves

(1) Hemolysis of RBCs (2) Denaturation of albumins by thrombin

(3) Inactivation of plasma clotting factors (4) Change of fibrinogen to fibrin by thrombin

Sol. Answer (4)

Platelet factor 3(Thromboplastin)

Blood platelets

Disintegrate and release

Thromboplastin(Phospholipid)

Injured tissue

Release

Ca2+

Prothrombin(Inactive plasma protein)

Ca2+

Thrombin (Active)

Fibrinogen(Soluble)

ThrombinFibrin(Insoluble)

FibrinPolymerization

Fibres(Clot)

5. If RBCs are placed in distilled water, the corpuscles will

(1) Burst (2) Increase in number (3) Shrink (4) Stick to each other

Sol. Answer (1)

When the RBCs are placed in water, the water moves from surrounding into the RBC by osmosis, which results

in swelling or bursting of RBC due to excess of water.

6. Universal recipient blood group is

(1) A+ (2) AB+ (3) B+ (4) O+

Sol. Answer (2)

Because person with AB blood group neither have anti-A nor anti-B antibodies but have both antigens (A and B).

7. A person with antigen A in RBC and antibody b in plasma belongs to blood group

(1) A (2) B (3) O (4) AB

Sol. Answer (1)

Person having A blood group have antigen A in RBC and antibody b in plasma.

8. The middle man of the body is

(1) Blood (2) Plasma (3) Lymph (4) Serum

Sol. Answer (3)

Lymph acts as 'middle man' which transports oxygen, food materials, hormone etc. to the body cells and

bring carbon dioxide and other metabolic wastes, from the body cells to blood and then finally pour the same

into the venous system.



(Lymph)

9. Lymph nodes

(1) Filter the lymph (2) Contain phagocytic cells

(3) Responsible for lymphocyte activation (4) All of these

Sol. Answer (4)

• Lymph is filtered through lymph nodes and they are abundant in neck, groin and armpits.

• Lymph nodes contain phagocytic cell which help to remove pathogens.

• Lymph nodes produce lymphocytes and then lymph transports lymphocytes and antibodies from the lymph

nodes to the blood.

10. Lymph differs from blood in possessing

(1) More proteins and less waste products

(2) Less proteins and more waste products

(3) More proteins and more waste products

(4) Less proteins and less waste products

Sol. Answer (2)

Blood Lymph

•

•

Consist mainly of plasma, RBC, WBC and platelets.

In plasma, more protein, Ca and phosphorus.

Amount of CO and metabolic

waste is normal.

•2

•

•

Consist of plasma, WBC.

In plasma, have few protein, Ca and phosphorus.

Amount of CO and metabolic

waste is much more.

•2

11. Read the following:

a. Lymph absorbs and transports fat from the intestine.

b. Lymph nodes produce fibrinogen.

c. Lymphatic capillaries present in the intestinal villi are known as lacteals.

d. Lymph transports oxygen only.

Which of these statements are true?

(1) a, c (2) b, d (3) c, d (4) a, b

Sol. Answer (1)

Statement b, is false because lymph nodes produce lymphocytes, not fibrinogen.

Statement d, is false, because lymph does not only transport O2 but it also transports CO

2, nutrients,

hormone etc.

(Circulatory Pathways)

12. Blood pumped by the heart passes into sinuses in

(1) Fishes (2) Earthworms

(3) Insects (4) Birds

Sol. Answer (3)

Because arthropods (insects) and noncephalopod molluscs have open circulatory system i.e., blood pumped

by heart passes through large vessels into open spaces or body cavity called sinus.

Rest all, i.e. fishes, earthworm and birds have closed circulatory system.



13. A patch of nodal tissue responsible for initiating the rhythmic contractile activity of heart is present in

(1) Lower left corner of the left ventricle

(2) Upper right corner of the right atrium

(3) Lower left corner of the right ventricle

(4) Upper left corner of the left atrium

Sol. Answer (2)

A patch of nodal tissue responsible initiating the rhythmic contractile activity of heart is SAN (Sino Atrial Node)

which is located at upper right corner of the right atrium.

14. Repolarisation of the ventricles is represented by

(1) P-wave (2) QRS-wave

(3) T-wave (4) Both P and T-wave

Sol. Answer (3)

P Q S

R

T

P Wave : Depolarisation of atria leads to contraction

QRS wave : Depolarisation of ventricle, which initiates ventricle contraction.

T wave : Represents the return of the ventricles from the excited to normal state i.e., repolarization of the

ventricles occur. End of T-wave mark the end of systole.

15. Time interval between the closure of semilunar valve and closure of AV valve is

(1) 0.3 s (2) 0.5 s (3) 0.1 s (4) 0.7 s

Sol. Answer (2)

Time interval between the closure of semilunar valve and closure of AV valve is the ventricular diastole time,

which is equal to 0.5 seconds.

16. If one litre of blood is drawn out of 5 litres from the body of man, how much blood would be left by the next

day?

(1) 5 litres (2) 4.5 litres (3) 4 litres (4) 3 litres

Sol. Answer (1)

Blood lost is compensated by blood cell formed by the bone marrow and RBC stored in spleen and liquid content

is provided from outside in the form of fluid etc, to compensate plasma.

17. The two auricles are demarcated externally from the ventricle by an irregular groove called

(1) Inter-auricular septum

(2) Inter-ventricular septum

(3) Coronary sulcus

(4) Inter-ventricular groove

Sol. Answer (3)

Coronary sulcus demarcated auricles from ventricle externally.



18. A cardiac cycle involves

(1) Joint diastole-ventricular systole-auricular systole

(2) Auricular systole-ventricular systole-complete cardiac diastole

(3) Auricular systole-joint diastole-ventricular systole

(4) Auricular systole-ventricular diastole-joint diastole

Sol. Answer (2)

Ventricularsystole 0.3 s

Auricular systole0.1 s

Cardiac cycle (0.8 second)

19. The duration of the ventricular diastole in a normal cardiac cycle is

(1) 0.3 second (2) 0.5 second

(3) 0.4 second (4) 0.7 second

Sol. Answer (2)

Ventricular systole duration = 0.3 seconds

Ventricular diastole duration = 0.8 – 0.3 = 0.5 seconds

20. Chordae tendinae in the heart are found in

(1) Ventricle (2) Left auricle

(3) Right auricle (4) Interventricular septum

Sol. Answer (1)

Chordae tendinae are the special fibrous cords that are attached to the flaps of the bicuspid and tricuspid valves

at one end and their other ends are attached to the ventricular wall with the special muscles known as papillary

muscle.

21. A portal system is one in which

(1) A vein starts from an organ and ends up in heart

(2) A vein starts from an organ and ends up in another organ

(3) A vein starts from heart and ends up in lungs

(4) None of these

Sol. Answer (2)

Heart

Organ 1 Organ 2

Portal systemArtery

Vein

Portal

Vein



(Double circulation)

22. Match column I with column II

Column I Column II

a. Capillaries (i) Valves

b. Veins (ii) Smooth muscles

c. Aorta (iii) Narrowest blood vessels

d. Tunica media (iv) Elastic artery

Select the alternative which shows the correct matching.

(1) a(iv), b(iii), c(i), d(ii) (2) a(iii), b(iv), c(ii), d(i) (3) a(iii), b(i), c(iv), d(ii) (4) a(ii), b(i), c(iv), d(iii)

Sol. Answer (3)

Capillaries are the narrowest blood vessels through which the exchange of gases and nutrient between the

blood and the tissue fluid occurs.

Veins have valves to prevent backflow of blood.

Aorta is an artery, which has thick elastic membrane in tunica interna.

Tunica media : It is the middle layer in the wall of artery and have smooth muscles mainly.

23. There is no capillary system in case of most of the invertebrates except

(1) Crustaceans (2) Cephalopods (3) Insects (4) Gastropods

Sol. Answer (2)

Cephalopods have closed circulatory system, rest all i.e. crustaceans, insect and gastropods have open

circulatory system.

24. The opening of pulmonary vein is without valve because

(1) It is a very small aperture

(2) It has low blood pressure

(3) Its opening is oblique

(4) None of these

Sol. Answer (3)

Veins have valves which prevent backward flow of blood except pulmonary vein because it has oblique opening.

25. The course of blood from the heart to the lungs and back to the heart is called

(1) Systemic circulation (2) Pulmonary circulation (3) Single circulation (4) Double circulation

Sol. Answer (2)

Pulmonary circulation = Right ventricle

↓Lungs

↓Left atrium

↓Systemic circulation = Left ventricle

↓Body parts

↓Right auricle

Double circulation = Pulmonary circulation + Systemic circulation



26. Hepatic portal system is present in

(1) Fishes, Amphibians and Reptiles (2) Reptiles and Birds

(3) All mammals (4) All vertebrates

Sol. Answer (4)

Hepatic portal system is characteristic feature of all vertebrates.

(Regulation of Cardiac Activity)

27. The strength of ventricular contraction increases when SAN is stimulated by

(1) Vagus nerve (2) Parasympathetic nerve

(3) Sympathetic nerve (4) All of these

Sol. Answer (3)

Because sympathetic nerve endings release adrenaline which stimulates the SAN. This accelerates the heart

beat, the strength of ventricular contraction and thereby the cardiac output.

(Disorders of Circulatory System)

28. Murmur occurs due to defect in

(1) Heart valves (2) SA node

(3) Bundle of His (4) Purkinje fibres

Sol. Answer (1)

In case of defective or damaged heart valves, their improper closure leads to leakage of blood which produces

an abnormal sound referred to as heart murmur.

29. Complete stoppage of heart beat is known as

(1) Cardiac arrest (2) Myocardial infarction

(3) Angina pectoris (4) Heart failure

Sol. Answer (1)

Cardiac arrest → Complete stoppage of heart beat

Myocardial infarction → Heart attack

Angina pectoris → Chest pain

Heart failure → Heart stops pumping

30. Which of the following diseases is also known as atherosclerosis?

(1) Hypertension (2) Angina pectoris

(3) Heart attack (4) Coronary artery disease (CAD)

Sol. Answer (4)

Hypertension – High blood pressure

Angina pectoris – Chest pain

Heart attack – Myocardial infarction

Coronary Artery Disease(CAD) – Atherosclerosis



SECTION - C


1. Match the items given in Column I with those in Column II and select the correct option given below

Column I Column II

a. Tricuspid valve (i) Between left atrium and left ventricle

b. Bicuspid valve (ii) Between right ventricle and pulmonary artery

c. Semilunar valve (iii) Between right atrium and right ventricle [NEET-2018]

(1) a(iii), b(i), c(ii) (2) a(i), b(iii), c(ii) (3) a(ii), b(i), c(iii) (4) a(i), b(ii), c(iii)

Sol. Answer (1)

Tricuspid valves are AV valve present between right atrium and right ventricle. Bicuspid valves are AV valve

present between left atrium and left ventricle. Semilunar valves are present at the openings of aortic and

pulmonary aorta.

2. Match the items given in Column I with those in Column II and select the correct option given below :

Column I Column II

a. Fibrinogen (i) Osmotic balance

b. Globulin (ii) Blood clotting

c. Albumin (iii) Defence mechanism [NEET-2018]

(1) a(iii), b(ii), c(i) (2) a(i), b(ii), c(iii) (3) a(ii), b(iii), c(i) (4) a(i), b(iii), c(ii)

Sol. Answer (3)

Fibrinogen forms fibrin strands during coagulation. These strands forms a network and the meshes of which

are occupied by blood cells, this structure finally forms a clot.

Antibodies are derived from γ-Globulin fraction of plasma proteins which means globulins are involved in defence

mechanisms.

Albumin is a plasma protein mainly responsible for BCOP.

3. The hepatic portal vein drains blood to liver from [NEET-2017]

(1) Heart (2) Stomach (3) Kidneys (4) Intestine

Sol. Answer (4)

In hepatic portal system, hepatic portal vein carries maximum amount of nutrients from intestine to liver.

4. Adult human RBCs are enucleate. Which of the following statement(s) is/are most appropriate explanation for

this feature? [NEET-2017]

(a) They do not need to reproduce

(b) They are somatic cells

(c) They do not metabolize

(d) All their internal space is available for oxygen transport

(1) Only (d) (2) Only (a) (3) (a), (c) and (d) (4) (b) and (c)

Sol. Answer (1)

In Human RBCs, nucleus degenerates during maturation which provide more space for oxygen carrying pigment

(Haemoglobin). It lacks most of the cell organelles including mitochondria so respires anaerobically.

5. Name the blood cells, whose reduction in number can cause clotting disorder, leading to excessive loss of

blood from the body. [NEET (Phase-2) 2016]

(1) Erythrocytes (2) Leucocytes

(3) Neutrophils (4) Thrombocytes



Sol. Answer (4)

Deduction in thrombocytes (platelets) can cause clotting disorder, leading to excessive loss of blood from the

body.

6. Serum differs from blood in [NEET (Phase-2) 2016]

(1) Lacking globulins (2) Lacking albumins

(3) Lacking clotting factors (4) Lacking antibodies

Sol. Answer (3)

Serum is plasma without clotting factors. It never clot.

7. Blood pressure in the pulmonary artery is [NEET-2016]

(1) Less than that in the venae cavae (2) Same as that in the aorta

(3) More than that in the carotid (4) More than that in the pulmonary vein

Sol. Answer (4)

Blood pressure in different blood vessels: Artery > Arteriole > Capillary > Venule > Vein (Vena cava)

8. In mammals, which blood vessel would normally carry largest amount of urea? [NEET-2016]

(1) Hepatic Portal Vein (2) Renal Vein (3) Dorsal Aorta (4) Hepatic Vein

Sol. Answer (4)

Urea is synthesized in liver. So maximum amount of urea is present in hepatic vein and minimum in renal vein.

9. It is much easier for a small animal to run uphill than for a large animal, because [NEET-2016]

(1) The efficiency of muscles in large animals is less than in the small animals

(2) It is easier to carry a small body weight

(3) Smaller animals have a higher metabolic rate

(4) Small animals have a lower O2 requirement

Sol. Answer (3)

Basal metabolic rate is inversely proportional to body size. So smaller animals have a higher metabolic rate.

10. Which one of the following is correct? [AIPMT-2015]

(1) Blood = Plasma + RBC + WBC + Platelets (2) Plasma = Blood – Lymphocytes

(3) Serum = Blood + Fibrinogen (4) Lymph = Plasma + RBC + WBC

Sol. Answer (1)

11. Blood pressure in the mammalian aorta is maximum during [AIPMT-2015]

(1) Diastole of the right atrium (2) Systole of the left atrium

(3) Diastole of the right ventricle (4) Systole of the left ventricle

Sol. Answer (4)

12. Erythropoiesis starts in [AIPMT-2015]

(1) Red bone marrow (2) Kidney (3) Liver (4) Spleen

Sol. Answer (3)

13. A man with blood group 'A' marries a woman with blood group 'B'. What are all the possible blood groups of

their offsprings? [AIPMT-2015]

(1) O only (2) A and B only

(3) A, B and AB only (4) A, B, AB and O

Sol. Answer (4)



14. How do parasympathetic neural signals affect the working of the heart? [AIPMT-2014]

(1) Reduce both heart rate and cardiac output

(2) Heart rate is increased without affecting the cardiac output

(3) Both heart rate and cardiac output increase

(4) Heart rate decreases but cardiac output increases

Sol. Answer (1)

Post-ganglionic fibers of parasympathetic nervous system secrete acetylcholine which decrease heart rate and

cardiac output.

15. Person with blood group AB is considered as universal recipient because he has [AIPMT-2014]

(1) Both A and B antigens on RBC but no antibodies in the plasma

(2) Both A and B antibodies in the plasma

(3) No antigen on RBC and no antibody in the plasma

(4) Both A and B antigens in the plasma but no antibodies

Sol. Answer (1)

Person with blood group AB has both A and B antigens on RBC but no antibodies in the plasma.

16. The diagram given here is the standard ECG of a normal person. The P-wave represents the [NEET-2013]

R

P Q ST

(1) Initiation of the ventricular contraction

(2) Beginning of the systole

(3) End of systole

(4) Contraction of both the atria

Sol. Answer (4)

17. Figure shows schematic plan of blood circulation in humans with labels A to D. Identify the label and give its

function/s [NEET-2013]

DA

BC

(1) B – Pulmonary artery-takes blood from heart to lungs, PO2 = 90 mm Hg

(2) C – Vena Cava-takes blood from body parts to right auricle, PCO2 = 45 mm Hg

(3) D – Dorsal aorta-takes blood from heart to body parts, PO2 = 95 mm Hg

(4) A – Pulmonary vein-takes impure blood from body parts, PO2 = 60 mm Hg



Sol. Answer (2)

18. A patient brought to a hospital with myocardial infarction is normally immediately given [AIPMT (Prelims)-2012]

(1) Cyclosporin-A (2) Statins (3) Penicillin (4) Streptokinase

Sol. Answer (4)

19. A certain road accident patient with unknown blood group needs immediate blood transfusion. His one doctorfriend at once offers his blood. What was the blood group of the donor? [AIPMT (Prelims)-2012]

(1) Blood group O (2) Blood group A (3) Blood group B (4) Blood group AB

Sol. Answer (1)

20. Which one of the following human organs is often called the “graveyard” of RBCs? [AIPMT (Mains)-2012]

(1) Liver (2) Gall bladder (3) Kidney (4) Spleen

Sol. Answer (4)

The older RBCs are removed from the circulation by the phagocytic cells of spleen mainly. Hence, spleen

is known as graveyard of RBC.

21. A person with unknown blood group under ABO system, has suffered much blood loss in an accident and needs

immediate blood transfusion. His one friend who has a valid certificate of his own blood type, offers for blood

donation without delay. What would have been the type of blood group of the donor friend?


(1) Type A (2) Type B (3) Type AB (4) Type O

Sol. Answer (4)

22. Arteries are best defined as the vessels which [AIPMT (Prelims)-2011]

(1) Carry blood from one visceral organ to another visceral organ

(2) Supply oxygenated blood to the different organs

(3) Carry blood away from the heart to different organs

(4) Break up into capillaries which reunite to form a vein

Sol. Answer (3)

Artery carries blood away from heart.

Vein carries blood towards the heart.

23. 'Bundle of His' is a part of which of the following organs in humans? [AIPMT (Prelims)-2011]

(1) Pancreas (2) Brain (3) Heart (4) Kidney

Sol. Answer (3)

Bundle of His is a part of heart located only in the ventricle wall.

24. Which one of the following plasma proteins is involved in the coagulation of blood? [AIPMT (Prelims)-2011]

(1) Fibrinogen (2) An albumin (3) Serum amylase (4) A globulin

Sol. Answer (1)

25. Which one of the following statements is correct regarding blood pressure? [AIPMT (Prelims)-2011]

(1) 190/110 mm Hg may harm vital organs like brain and kidney

(2) 130/90 mm Hg is considered high and requires treatment

(3) 100/55 mm Hg is considered an ideal blood pressure

(4) 105/50 mm Hg makes one very active



Sol. Answer (1)

Blood pressure of an individual is 140/90 or higher, it shows hypertension which leads to heart diseases

and also affect vital organs like brain and kidney.

26. Given below is the ECG of a normal human. Which one of its components is correctly interpreted below?


R

P Q ST

(1) Peak P and Peak R together – systolic and diastolic blood pressures

(2) Peak P– Initiation of left atrial contraction only

(3) Complex QRS – One complete pulse

(4) Peak T – Initiation of total cardiac contraction

Sol. Answer (3)

P wave : Atrial depolarization

QRS wave : Ventricular depolarisation / One complete pulse systole (diastole)

T wave : Ventricular repolarisation

27. What is true about RBCs in humans? [AIPMT (Prelims)-2010]

(1) They do not carry CO2 at all

(2) They carry about 20-25 percent of CO2

(3) They transport 99.5 percent of O2

(4) They transport about 80 percent oxygen only and the rest 20 percent of it is transported in dissolved state

in blood plasma

Sol. Answer (2)

28. If due to some injury the chordae tendinae of the tricuspid valve of the human heart is partially non-functional,

what will be the immediate effect? [AIPMT (Prelims)-2010]

(1) The flow of blood into the pulmonary artery will be reduced

(2) The flow of blood into the aorta will be slowed down

(3) The pacemaker will stop working

(4) The blood will tend to flow back into the left atrium

Sol. Answer (1)

The tricuspid valve is present between right atrium and right ventricle and then from right ventricle blood goes

to lungs via pulmonary artery.

The chordae tendinae which is attached to the flaps of tricuspid valve and prevent it from collapsing back into

the atria during powerful ventricular contraction and if in case, the chordae tendinae of the tricuspid valve

become partially non-functional then the flow of blood into the pulmonary artery will be reduced.



29. Given below are four statements (a-d) regarding human blood circulatory system

(a) Arteries are thick-walled and have narrow lumen as compared to veins

(b) Angina is acute chest pain when the blood circulation to the brain is reduced

(c) Persons with blood group AB can donate blood to any person with any blood group under ABO system

(d) Calcium ions play a very important role in blood clotting

Which two of the above statements are correct? [AIPMT (Mains)-2010]

(1) (a) & (d) (2) (a) & (b) (3) (b) & (c) (4) (c) & (d)

Sol. Answer (1)

Statement(b) is wrong because acute chest pain appears when no enough oxygen is reaching the heart

muscle.

Statement(c) is wrong, because AB is universal acceptor, not universal donor.

30. The haemoglobin content per 100 ml of blood of a normal healthy human adult is [AIPMT (Mains)-2010]

(1) 5 - 11 g (2) 25 - 30 g (3) 17 - 20 g (4) 12 - 16 g

Sol. Answer (4)

31. The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC, because "O" in

it refers to having: [AIPMT (Prelims)-2009]

(1) Overdominance of this type on the genes for A and B types

(2) One antibody only – either anti-A or anti-B on the RBCs

(3) No antigens A and B on RBCs

(4) Other antigens besides A and B on RBCs

Sol. Answer (3)

32. Compared to blood our lymph has [AIPMT (Prelims)-2009]

(1) Plasma without proteins (2) More WBCs and no RBCs

(3) More RBCs and less WBCs (4) No plasma

Sol. Answer (2)

Lymph has more WBC, because lymph nodes produce lymphocytes and the lymph takes lymphocytes and

antibodies from the lymph nodes.

33. There is no DNA in [AIPMT (Prelims)-2009]

(1) Mature RBCs (2) A mature spermatozoan

(3) Hair root (4) An enucleated ovum

Sol. Answer (1)

Matured RBCs do not have cell organelles including nucleus, golgi bodies, mitochondria, ribosomes, centrioles

and endoplasmic reticulum.

34. In a standard ECG which one of the following alphabets is the correct representation of the respective activity of

the human heart? [AIPMT (Prelims)-2009]

(1) S – start of systole (2) T – end of diastole

(3) P – depolarisation of the atria (4) R–repolarisation of ventricles

Sol. Answer (3)

P wave : Depolarization of atria

QRS wave : Depolarisation of ventricles

T wave : Repolarisation of ventricles



35. Globulins contained in human blood plasma are primarily involved in: [AIPMT (Prelims)-2009]

(1) Osmotic balance of body fluids (2) Oxygen transport in the blood

(3) Clotting of blood (4) Defence mechanisms of body

Sol. Answer (4)

36. The most active phagocytic white blood cells are [AIPMT (Prelims)-2008]

(1) Neutrophils and monocytes (2) Neutrophils and eosinophils

(3) Lymphocytes and macrophages (4) Eosinophils and lymphocytes

Sol. Answer (1)

37. Which type of white blood cells are concerned with the release of histamine and the natural anticoagulant

heparin? [AIPMT (Prelims)-2008]

(1) Monocytes (2) Neutrophils (3) Basophils (4) Eosinophils

Sol. Answer (3)

38. The haemoglobin of a human foetus [AIPMT (Prelims)-2008]

(1) Has a higher affinity for oxygen than that of an adult

(2) Has a lower affinity for oxygen than that of the adult

(3) Its affinity for oxygen is the same as that of an adult

(4) Has only 2 protein subunits instead of 4

Sol. Answer (1)

39. In humans, blood passes from the post caval to the diastolic right atrium of heart due to


(1) Pressure difference between the post caval and atrium

(2) Pushing open of the venous valves

(3) Suction pull

(4) Stimulation of the sino auricular node

Sol. Answer (1)

40. Consider the following statements about biomedical technologies

a. During open heart surgery blood is circulated in the heart-lung machine.

b. Blockage in coronary arteries is removed by angiography.

c. Computerised Axial Tomography (CAT) shows detailed internal structure as seen in a section of body.

d. X-ray provides clear and detailed images or organs like prostate glands and lungs.

Which two of the above statements are correct? [AIPMT (Prelims)-2008]

(1) a and b (2) b and d (3) c and d (4) a and c

Sol. Answer (4)

41. If you suspect major deficiency of antibodies in person, to which of the following would you look for

confirmatory evidence? [AIPMT (Prelims)-2007]

(1) Haemocytes (2) Serum albumins

(3) Serum globulins (4) Fibrinogen in the plasma

Sol. Answer (3)



42. Which one of the following mammalian cells is not capable of metabolising glucose to carbon-dioxide

aerobically? [AIPMT (Prelims)-2007]

(1) Red blood cells (2) White blood cells

(3) Unstriated muscle cells (4) Liver cells

Sol. Answer (1)

43. A drop of each of the following, is placed separately on four slides. Which of them will not coagulate?


(1) Whole blood from pulmonary vein

(2) Blood plasma

(3) Blood serum

(4) Sample from the thoracic duct of lymphatic system

Sol. Answer (3)

44. The ‘blue baby’ syndrome results from [AIPMT (Prelims)-2006]

(1) Excess of chloride (2) Methaemoglobin

(3) Excess of dissolved oxygen (4) Excess of TDS (Total Dissolved Solids)

Sol. Answer (2)

45. G-6-P dehydrogenase deficiency is associated with haemolysis of [AIPMT (Prelims)-2005]

(1) Lymphocytes (2) RBCs

(3) Platelets (4) Leucocytes

Sol. Answer (2)

46. Which of the following substances, if introduce in the blood stream, would cause coagulation, at the site of its

introduction? [AIPMT (Prelims)-2005]

(1) Fibrinogen (2) Prothrombin (3) Heparin (4) Thromboplastin

Sol. Answer (4)

47. Lymph collected from left side of the body collected through thoracic duct and finally opens into

(1) Right sub clavian vein (2) Righ sub clavian artery

(3) Left sub clavian vein (4) Left sub clavian artery

Sol. Answer (3)

Because thoracic duct is located on the left side and further this duct will drain the lymph into subclavian

vein located on the left side only.

48. Systemic heart refers to

(1) The heart that contracts under stimulation from nervous system

(2) Left auricle and left ventricle in higher vertebrates

(3) Entire heart in lower vertebrates

(4) The two ventricles together in humans

Sol. Answer (2)

Systemic heart means oxygenated heart which supplies blood to the body parts.



49. Which of the following layer of heart is related to difference in thickness of different chambers of heart?

(1) Outer fibrous coat (2) Epicardium (3) Myocardium (4) Endocardium

Sol. Answer (3)

The heart has an outermost smooth coelomic epithelium - the visceral pericardium.

The middle thick muscular layer called myocardium, made up of muscle fibres.

Innermost layer i.e., endocardium.

50. Which of the following are in direct contact with the AV valves and prevent these from collapsing back into atria?

(1) Chordae tendinae (2) Papillary muscles (3) Columnae carnae (4) Musculi pectinati

Sol. Answer (1)

Special fibrous cords called the chordae tendinae are attached to the flaps of the bicuspid and tricuspid

valves at one end and their other ends are attached to the ventricular wall with the special muscles. The

papillary muscles. The chordae tendinae prevent the bicuspid and tricuspid valves from collapsing back into

the atria during powerful ventricular contraction.

Columnae carinae : They are the rounded or irregular muscular column which project from the inner surface

of the right and left ventricles of heart.

Musculi pectinati : They are the parallel ridges in the walls of the atria of the heart.

51. The pacesetter in the heart is called

(1) Sino-atrial node (SAN) (2) Atrio-ventricular node (AVN)

(3) Purkinje fibres (4) Papillary muscle

Sol. Answer (2)

Sino-atrial node(SAN) is called pacemaker

Atrio-ventricular node (AVN) is called pacesetter.

52. The correct route through which impulse travels in the heart is

(1) SA node → Purkinje fibres → bundle of His → AV node → heart muscles

(2) SA node → AV node → bundle of His → Purkinje fibres → heart muscles

(3) AV node → bundle of His → SA node → Purkinje fibres → heart muscles

(4) AV node → SA node → Purkinje fibres → bundle of His → heart muscles

Sol. Answer (2)

SA node (wave of contraction get originated at SA node)

↓AV node

↓Bundle of His

↓Purkinje's fibre (now, the impulse stimulates the ventricles to contract simultaneously)

53. Bundle of His is a network of

(1) Muscle fibres distributed throughout the heart walls

(2) Muscle fibres found only in the ventricle wall

(3) Nerve fibres distributed in ventricles

(4) Nerve fibres found throughout the heart



Sol. Answer (2)

Bundle of His are muscle fibres which originate from AV node and present on the each ventricle wall.

54. The cardiac pacemaker in a patient fails to function normally. The doctors find that an artificial pacemaker is

to be grafted in him. It is likely that it will be grafted at the site of

(1) Atrioventricular bundle (2) Purkinje system

(3) Sinoatrial node (4) Atrioventricular node

Sol. Answer (3)

Sinoatrial node is also called pacemaker because it is the site which generates the maximum number of action

potential i.e., 70–75 min–1 and is responsible for initiating and maintaining the rhythmic contractile activity of

the heart.

55. Impulse of heart beat originates from

(1) SA node (2) AV node (3) Vagus nerve (4) Cardiac nerve

Sol. Answer (1)

SA node is also known as pacemaker because the contraction of atria is initiated and activated by SA node.

56. Rate of heart beat is determined by

(1) Purkinje fibres (2) Papillary muscles (3) AV-node (4) SA-node

Sol. Answer (4)

It is the site which generates the maximum number of action potential i.e. 70–75 min–1 and is responsible

for initiating and maintaing the rhythmic contractile activity of the heart.

57. The heart sound ‘dup’ is produced when

(1) Mitral valve is closed (2) Semilunar valves at the base of aorta get closed

(3) Tricuspid valve is opened (4) Mitral valve is opened

Sol. Answer (2)

The first heart sound 'LUBB' is produced by closure of bicuspid and tricuspid valves.

The second heart sound 'DUP' is produced by closure of aortic and pulmonary semilunar valves.

58. At the end of joint diastole ventricle is

(1) Completely filled by blood (2) Two third filled by blood

(3) One third filled by blood (4) Completely empty

Sol. Answer (2)

During joint diastole, in the beginning of the ventricle diastole there is first rapid filling due to opening of AV

valves then the blood fills into ventricles with slow pace called diastasis or slow filling. Due to this, ventricle

is two-thirds filled by blood.

Remaining 1/3rd is filled during atrial contraction.

59. To obtain a standard ECG, a patient is connected to the machine with three electrodes attached

(1) One to each wrist and to the left ankle (2) One to each ankle and to the left wrist

(3) One to each wrist and to the left chest region (4) One to each ankle and to the left chest region

Sol. Answer (1)

To obtain a standard, ECG, three electrodes of the machine are attached one to each wrist and to the left

ankle of patient.



60. When the heart muscles receive insufficient oxygen, it is indicated in the ECG as

(1) Enlarged P-wave (2) Depressed S-T segment (3) Flattened T-wave (4) Both (2) & (3)

Sol. Answer (4)

S-T segment is elevated in acute myocardial infarction and depressed when the heart muscle receives insufficient

oxygen.

T wave is flat when heart muscle receives insufficient oxygen as in atherosclerotic heart disease and it may be

elevated when the body's potassium level is increased.

61. In what way pulmonary artery is different from pulmonary vein?

(1) Its lumen is broad (2) Its wall is thick

(3) It has valves (4) It does not possess endothelium

Sol. Answer (2)

Artery has thick wall, blood flows with more pressure. Thickness of artery is due to tunica media.

62. Difference between pulmonary artery and pulmonary vein is that the pulmonary artery has

(1) No endothelium (2) Valves (3) Thicker wall (4) Oxygenated blood

Sol. Answer (3)

Artery has thick wall, blood flows with more pressure. Thickness of artery is due to tunica media.

63. In veins, valves are present to check backward flow of blood flowing at

(1) Atmospheric pressure (2) High pressure

(3) Low pressure (4) All of these

Sol. Answer (3)

Artery have high pressure

Veins have low pressure, thin walls

64. Fastest distribution of some injectible material/medicine with no risk of any kind can be achieved by injecting

it into the

(1) Muscles (2) Arteries

(3) Veins (4) Lymph vessels

Sol. Answer (3)

Because veins carry blood towards the heart and then heart pumps blood to all organs.

65. An adult human with average health has systolic and diastolic pressures as

(1) 120 mm Hg and 80 mm Hg (2) 50 mm Hg and 80 mm Hg

(3) 80 mm Hg and 80 mm Hg (4) 70 mm Hg and 120 mm Hg

Sol. Answer (1)

Normal blood pressure 120(systolic pressure) / 80 (Diastolic pressure)

66. Which vertebrate organ receives only oxygenated blood?

(1) Spleen (2) Liver (3) Gill (4) Lung

Sol. Answer (1)

Liver : Carries deoxygenated blood via hepatic portal vein.

Lung : Carries deoxygenated blood via pulmonary artery.



67. The thickening of walls of arteries is called

(1) Arteriosclerosis (2) Arthritis (3) Aneurysm (4) Both (2) & (3)

Sol. Answer (1)

Arteriosclerosis : Thickening of walls due to calcification in old age.

Arthritis : It is a disorder in which inflammation of the joints occurs. It is characterized by pain, swelling,

redness, heat.

Aneurysm : Abnormal widening and ballooning of a portion of an artery due to weakness in the wall of blood

vessel.

68. Which of the following cannot be taken as a feature of open type circulatory system?

(1) Low pressure system (2) Well regulated blood supply to different organs

(3) Blood returns to the heart slowly (4) Non formation of capillaries

Sol. Answer (2)

Well-regulated blood supply to different organs occurs in closed circulatory system, in which blood flows in

the blood vessel.

69. Which of the following blood vessels bypass are present in the circulatory system before birth?

(1) Foramen ovale (2) Fossa ovalis (3) Ductus arteriosus (4) Both (1) & (3)

Sol. Answer (4)

Before birth, the major portion blood from the right side bypasses the pulmonary circulation through foramen

ovale and ductus arteriosus. At the time of birth with the start of breathing, these bypass cease to act.

Foramen ovale closes to become fossa ovalis.

Ductus arteriosus closes to become ligamentum arteriosum.

70. Isovolumetric systole is duration between

(1) Closure of AV valve and opening of semilunar valve (2) Closure of semilunar valve and opening of AV valve

(3) Closure of tricuspid and closure of bicuspid valve (4) Closure of tricuspid and opening of bicuspid valve

Sol. Answer (1)

During isovolumetric contraction volume of blood does not change even though ventricular continue contracting.

71. High level of which ions change the strength of contraction

(1) Ca2+ (2) K+ (3) Na+ (4) All of these

Sol. Answer (4)

Elevated blood level of K+ or Na+ decreases heart rate and contractility

An excess of Ca2+ increases heart rate.

SECTION - D


1. A : The cardiac impulse which originates from SA node in mammalian heart cannot spread directly from atria to

ventricles.

R : In mammalian heart there is no continuity between cardiac muscle fibres of atria and those of ventricles

except AV bundles.

Sol. Answer (1)

SA node → AV node → Bundle of His → Bundle branch → Purkinje fibre → Ventricle wall



2. A : First phase of ventricular filling is rapid and causes 3rd sound of heart.

R : It is because of auricular systole.

Sol. Answer (3)

It is because of opening of AV valve.

3. A : Dub is a long and sharp sound.

R : It is caused by closing of atrio ventricular valves.

Sol. Answer (4)

Dup has high pitch and of short duration.

4. A : Portal system consists of veins which start from capillaries and end into capillaries.

R : All vertebrates have hepatic portal system.

Sol. Answer (2)

A unique vascular connection exists between the digestive tract and liver called hepatic portal system.

5. A : Left ventricle pumps blood at a much higher pressure to all body parts involved in systemic circulation.

R : The muscular wall of the left ventricle is two to four times as thick as the wall of right ventricle.

Sol. Answer (1)

Left ventricle has thickest wall.

6. A : The resting heart rate, about 75/minutes, usually is lower than the autorhythmic rate of the SA node

(90 – 100 beats/minute).

R : At rest condition, the parasympathetic effects dominate.

Sol. Answer (1)

The signals from parasympathetic nervous system decreases the heart rate.

7. A : Elevated levels of Na+ increases the heart rate and contractility.

R : Elevated Na+ level increase the excitability of SA node.

Sol. Answer (4)

Elevated levels of Na+ decreases the heart rate and contractility.

8. A : Endocardium provides a smooth lining for the inside of the heart and covers the valves of the heart.

R : Endocardium is continuous with the endothelial lining of the large blood vessels associated with the heart

and the rest of the cardiovascular system.

Sol. Answer (2)

Inner wall of heart is endocardium.

9. A : Isovolumetric systole of a normal cardiac cycle is responsible for the opening of semilunar valves causing

the blood flow into aortic aorta and pulmonary aorta.

R : During isovolumetric systole, intraventricular pressure increases as semilunar and AV valves are closed and

ventricles are contracting.

Sol. Answer (1)

There is no change in volume of blood in ventricles during isovolumetric systole.

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