ocr as/a level biology a (h020/h420) - schudio · 2020. 3. 25. · ocr as/a level biology a...

© OCR 2016 Page 1

OCR AS/A Level Biology A (H020/H420) Module 2 Topic Test – Foundations in Biology

1 Zinc ions are necessary for the enzyme carbonic anhydrase to work.

Which statement correctly describes the nature and function of zinc ions in their

interaction with carbonic anhydrase?

A inorganic ions and coenzymes

B vitamins and prosthetic groups

C inorganic ions and prosthetic groups

D vitamins and coenzymes

Your answer [1]

2 Three types of microscope are listed below.

Select the row that shows the correct use for each type of microscope.

Type of microscope and what it is used to observe

Light microscope

Transmission electron microscope

Laser scanning confocal microscope

A

an object at a certain depth within a cell

cell surfaces

organelles

B


cell surfaces

whole cells and tissues

C


organelles

cell surfaces

D


organelles


Your answer [1]

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3 A length of DNA has the base sequence AATCGCGGTCGCTCA.

Select the row that shows the correct complementary DNA strand and the sequence of

mRNA made during transcription of the DNA sequence above.

Complementary DNA sequence mRNA sequence

A AATCGCGGTCGCTCA UUAGCGCCAGCGAGU

B TTAGCGCCAGCGAGT

UUAGCGCCAGCGAGU C TTAGCGCCAGCGAGT TTAGCGCCAGCGAGT

D TTAGCGCCAGCGAGT AAUCGCGGUCGCUCA

Your answer [1]

4 There are two types of nuclear division, mitosis and meiosis. Meiosis incorporates two

divisions of the nucleus.

Which table shows the correct results of nuclear division?

A C

Genetic

Variation

Reduction

division

Genetic

Variation

Reduction

division

Mitosis X X Mitosis X ✓

Meiosis 1 ✓ ✓ Meiosis 1 ✓ X

Meiosis 2 X X Meiosis 2 ✓ ✓

B D

Genetic

Variation

Reduction

division

Genetic

Variation

Reduction

division

Mitosis X X Mitosis X X

Meiosis 1 ✓ ✓ Meiosis 1 ✓ ✓

Meiosis 2 ✓ X Meiosis 2 X ✓

Your answer [1]

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5 Which of the following formulae of fatty acids represents a saturated fatty acid?

Statement 1: Palmitic acid, C15H31COOH

Statement 2: Oleic acid, C17H33COOH

Statement 3: Linoleic acid, C17H31COOH

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Your answer [1]

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6 (a) Glucose can be moved into cells by facilitated diffusion using proteins called GLUT

proteins. These proteins expose a single binding site on one side of the membrane.

Glucose binds to this site and causes a change in the shape of the protein. This

change moves the glucose across the membrane and releases it on the other side.

(i) Explain why facilitated diffusion via GLUT proteins requires no metabolic

energy.

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

…………………………………………………………………………………… [2]

(ii) Glucose can also be absorbed by an active process which requires metabolic

energy. What is the immediate source of this energy in cells?

………………………………………………………………………………… [1]

(iii) Explain why glucose cannot pass through a cell membrane by simple

diffusion.

……………………………………………………………………………………..

……………………………………………………………………………………..

……………………………………………………………………………………..

…………………………………………………………………………………… [2]

(b) A student investigated the effect of alcohol on the permeability of membranes in

plant cells. The student wanted to find the minimum concentration of alcohol at

which all the cells became permeable to the stain Evans Blue. Evans Blue stains

the nucleus of the cell.

The student followed this method:

The student placed samples of onion epidermis into different concentrations of

ethanol.

After five minutes a few drops of Evans Blue stain was added to each sample.

After a further five minutes, the samples were viewed using a light

microscope.

The student observed 20 cells and recorded how many contained a blue

nucleus.

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Table 21.1 shows the student’s results. Table 21.1

(i) Identify one limitation of the method the student followed.

…………………………………………………………………………………………

…………………………………………………………………………………… [1]

(ii) On evaluating the results the student decided to use a narrower range of

ethanol concentrations.

Suggest what range of ethanol concentrations the student should use and

give a reason for your choice.

..…………………………………………………………………………………………

..…………………………………………………………………………………………

..…………………………………………………………………………………………

…………………………………………………………………………..……… [2]

(iii) How would using a narrower range of alcohol concentrations improve the

investigation?

……..……………………………………………………………………………………

…...………………………………………………………………………………… [1]

Concentration of ethanol (%)

Number of cells with a blue nucleus

% cells with blue nucleus

0 1 5

10 4 20

20 16 80

30 20 100

40 20 100

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7 (a) Fig. 22.1 shows a transverse section of the stem of a typical pondweed viewed

using a ×10 objective lens. Part of a graticule is shown below the stem. The

markings on the graticule are 0.1 mm apart.

(i) Measure the width of the stem between points A and B.

Give your answer to the nearest 0.1 mm.

Answer…………………………………… [1]

(ii) Calculate the magnification of the image in Fig. 22.1.

Answer………………………………….. [2]

(iii) The thin stem and thin cell walls do not provide much support for the leaf.

Suggest how the leaf is supported.

………………………………………………………………………………………

………………………………………………………………………………………

…………………………………………………………………………………… [2]

A B

vascular

bundle

air space

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(b) A student was asked to view cells from the phloem in transverse section using a

high power objective lens. Fig. 22.2 shows two diagrams of phloem tissue.

(i) Which diagram is the more accurate representation of what the student could

see?

Justify your decision using two separate features of the diagrams.

………………………………..…………….…………………………………………..

…………………………………..…………….………………………………………..

…………………………………..……………….……………………………………..

………………………………..……………………………………………….. [2]

(ii) State what is meant by the resolution of a microscope.

…………..………………………………………………………………………………

………………………………………………………………………………… [1]

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(iii) The slide viewed to draw the diagrams in Fig. 22.2 had been stained.

Table 22.1 shows a list of stains and the cell feature that can be stained.

Which stain had the student used? Explain your answer.

……………………………..……....……………………………………………………

…………………………..………....……………………………………………………

……………………………..……....……………………………………………………

……………………………………..…………………………………………. [2]

8 Amylase activity is increased in the presence of chloride ions.

State the name given to any inorganic ion that increases the activity of an enzyme.

……………………………………………………………………………………….………… [1]

Stain

Cell feature stained

Nile blue nuclei

eosin cytoplasm

Sudan red cell membrane

iodine starch

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9 (i) Outline how the process of DNA replication is completed, following the pairing

of nitrogenous bases.

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

……………………………………………………………………………………. [3]

(ii) Why is DNA replication described as semi-conservative?

…………………………………………….…………………………………………..

………………………………………………………………………………… [1]

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10 A group of microorganisms called slime moulds includes the species Dictyostelium

discoideum.

1 When plenty of food is available this slime mould exists as single-celled individuals

which feed and reproduce asexually.

The slime mould cells feed on bacteria.

The slime mould cells are attracted to folic acid which has been released by the

bacteria.

2 When food becomes scarce the slime mould cells release a chemical (cAMP) which

attracts other slime mould cells.

3 The slime mould cells then group and stick together to form a multicellular mass

called a grex.

The grex moves in a coordinated way in search of a more suitable environment.

As the grex moves, the cells release the chemical DIF. DIF causes some cells to

become stalk cells and others to become spore cells.

4 When the grex reaches suitable conditions, it forms a fruiting body consisting of a

stalk and spores.

These spores are released and develop into new, individual, slime mould cells.

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(a) (i) Suggest the type of cell division used by D. discoideum for reproduction during

stage 1 of its life cycle.

..................................................................................................................... [1]

(ii) At what stage of the life cycle does differentiation begin?

................................................................................................................... [1]

(b) Communication and cooperation between cells is essential for the survival of

D. discoideum.

(i) State the correct term for communication between cells.

.................................................................................................................. [1]

(ii) Describe two examples of communication between cells that occur during the

life cycle of D. discoideum.

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................

..................................................................................................................... [2]

(iii) The plasma membranes of the slime mould cells are specially adapted for

communication.

Suggest how the plasma membrane of D. discoideum is adapted for cell

communication.

…………………………………………………………………………………………

..……………………………………………………………………………………….

……………………………………………………………………………….……….

………………………………………………………………………………. [2]

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11 (c) In the past, beef was preserved by adding salt.

Explain how salting preserves food.

................................................................................................................................

................................................................................................................................

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................................................................................................................................

................................................................................................................................

...............................................................................................................................

...............................................................................................................................

...............................................................................................................................

....................................................................................................................... [3]

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12

(a) (i) Name the cell components labelled A and B.

A .........................................................................................................................

B .......................................................................................................... [2]

(ii) State the functions of the components labelled C and D.

C ........................................................................................................................

............................................................................................................................

............................................................................................................................

D .........................................................................................................................

............................................................................................................................

............................................................................................................... [2]

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(b) A student suggested that the details of component C could be seen clearly with a

very good light microscope.

Explain why the student is not correct.

......................................................................................................................................

......................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

............................................................................................................................. [2]

13 (a) Alcohol dehydrogenase is a protein molecule that is present in the liver. The

molecule breaks down alcohols and other chemicals that would otherwise be toxic

to the body.

Name the group of biological molecules to which alcohol dehydrogenase belongs.

.......................................................................................................................... [1]

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(b) In 1985, health concerns were raised when the compound diethylene glycol (DEG)

was detected in samples of wine. The DEG had been added, illegally, to make the

wine taste sweeter.

In the liver, DEG is broken down by alcohol dehydrogenase to form a toxic product.

Alcohol dehydrogenase also breaks down ethanol, the key ingredient in alcoholic

drinks such as wine, to form a non-toxic product.

Fig. 2.1 shows the structures of DEG and ethanol.

(i) Using the information in Fig. 2.1, explain why alcohol dehydrogenase is able

to breakdown both ethanol and DEG.

............................................................................................................................

............................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

....................................................................................................................... [3]

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(ii) Suggest why DEG-contaminated wines with a high ethanol content may result

in less DEG poisoning than contaminated wines with a low ethanol content.

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................

....................................................................................................................... [3]

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14 Genes are important in the process of natural selection. Genes are made of DNA.

(i) State the role of a gene.

............................................................................................................................

................................................................................................................ [1]

(ii) Explain how the structure of DNA allows replication.

............................................................................................................................

............................................................................................................................

............................................................................................................................

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...........................................................................................................................

................................................................................................................. [5]

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15 (a) Amino acids form part of the structure of proteins.

(i) State the name given to the sequence of amino acids in a protein molecule.

................................................................................................................. [1]

(ii) Draw the general structure of an amino acid molecule in the space below.

[3]

(b) Collagen is an important fibrous protein which forms part of the wall of blood

vessels.

State one property of collagen that makes it a useful component of blood vessel

walls.

……………………………………………………………………………………... [1]

(c) Another protein that is important in mammals is haemoglobin.

State one function of haemoglobin.

...............................................................................................................................

....................................................................................................................... [1]

[Total Marks: 64]

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MARK SCHEME

Question Mks Answer Question Source and Guidance Notes Topics Demand

1 1 C Q4-GCE-Biology A-Specimen-H020/01 Foundations in Biology; Enzymes

M

2 1 D Q6-GCE-Biology A-Specimen-H020/01 Foundations in Biology; Cell Structure

M

3 1 B Q9-GCE-Biology A-Specimen-H020/01 Foundations in Biology; Nucleotides and nucleic acids

M

4 1 B Q11-GCE-Biology A-Specimen-H020/01 Foundations in Biology; Cell division, cell diversity and cellular organisation

M

5 1 D Q18-GCE-Biology A-Specimen-H020/01 Foundations in Biology; Biological molecules

H

6 (a)(i) 2 particles have (their own) kinetic energy ✓

(movement) down concentration gradient ✓

Q21(a)(i)-GCE-Biology -Specimen-H020/01

ALLOW glucose for particles.

ALLOW from high(er) concentration to low(er)

concentration Foundations in Biology; Biological molecules

L,M,H

6 (a)(ii) 1 ATP ./ Q21(a)(ii)-GCE-Biology A-Specimen-H020/01

ALLOW adenosine triphosphate

6 (a)(iii) 2 phospholipids act as a barrier ✓

(glucose) molecules too large ✓

Q21(a)(iii)-GCE-Biology -Specimen-H020/01

ALLOW (glucose) not soluble in phospholipid bilayer

because of polar –OH groups for 2 marks

6(b)(i) 1 one from

volume of ethanol not given ✓

same onion / size of onion epidermis / position of

epidermis in onion not stated ✓

Q21(b)(i)-GCE-Biology A-Specimen-H020/01 Practical Skills; Planning; Analysis; Evaluation

L,M

6(b)(ii) 2 20–30% ✓

lowest concentration must be between 20 and

30% ✓

Q21(b)(ii)-GCE-Biology A-Specimen-H020/01

idea that 100% blue nuclei is not reached at 20% but is reached at 30%

Practical Skills; Planning; Analysis; Evaluation

L,M

6(b)(iii) 1 idea of more accurate determination of

permeability ✓

Q21(b)(iii)-GCE-Biology A-Specimen-H020/01 Practical Skills; Planning; Analysis; Evaluation

L,M

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7(a)(i) 1 1.7 mm ✓ Q22(a)(i)-GCE-Biology A-Specimen-H020/01

Practical Skills; Implementing L,M

7(a)(ii) 2 × 50 ✓

Q22(a)(ii)-GCE-Biology A-Specimen-H020/01

ALLOW 1 mark for correct working e.g. 80/1.6

ALLOW answer in the range of 48–51

7(a)(iii) 1 air spaces give buoyancy ✓

supported by (surrounding) water ✓

Q22(a)(iii)-GCE-Biology A-Specimen-H020/01

7(b)(i) 2 B

comment about detail of organelles ✓

comment about shapes of cells ✓

Q22(b)(i)-GCE-Biology A- Specimen-H020/01

No Mark for identification of B

e.g. light microscope would not allow nuclear pores /

ribosomes / endoplasmic reticulum / plasmodesmata to be

seen.

e.g. sieve tube elements are angular / hexagonal. Practical Skills; Implementing L,M

7(b)(ii) 1 the ability to, see more detail / separate two

objects ✓


7(b)(iii) 2 Nile blue ✓

to increase contrast / to make nuclei visible / to

show no nuclei in sieve tubes ✓

Q22(b)(iii)-GCE-Biology A-Specimen-H020/01

8 1 cofactor ./ Q2(d)-GCE-Biology A-Specimen-H020/02 IGNORE coenzyme.

Foundations in Biology; Biological molecules

L

9(i) 3 (involves) DNA polymerase ./

sugar-phosphate backbone

(re)forms/condensation reaction between

phosphate and sugar ./

DNA winds into double helix ./

Q6(b)(i)-GCE-Biology A-Specimen-H020/02

ALLOW higher level answers

e.g. role of DNA ligase in joining sugar-phosphate

backbone lagging strand filled in with Okazaki fragments. Foundations in Biology; Nucleotides and nucleic acids

M,H

9(ii) 1 (new molecule consists of) one old strand and one new strand ./


10(a)(i) 1 mitosis ; Q5(a)(i)-GCE-Biology -June 2014-F211/01 CREDIT correct spelling only

ACCEPT binary fission

Foundations in Biology; Cell division, cell diversity and cellular organisation

L,M

10(a)(ii) 1 in the grex / 3 ; Q5(a)(ii)-GCE-Biology -June 2014-F211/01

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10(b)(i) 1 cell signalling ; Q5(b)(i)-GCE-Biology -June 2014-F211/01


L,H

10(b)(ii) 2

1 attraction of cell(s) to folic acid from bacteria ; 2 attraction of cells to each other by cAMP ; 3 coordinated movement in grex ; 4 differentiation / described, of (grex / slime

mould) cells in response to DIF ;

Q5(b)(ii)-GCE-Biology -June 2014-F211/01

NOTE must name the chemical involved for description

(except mp 3 coordinated movement)

ACCEPT attraction of cells to bacteria by folic acid

IGNORE makes cells stick together

10(b)(iii) 2 contains , receptors / glycoproteins / glycolipids /

glycocalyx ;

for , folic acid / cAMP / DIF;

Q5(b)(iii)-GCE-Biology -June 2014-F211/01

DO NOT CREDIT consists of receptors

11 3 1 reduces , water potential / Ψ , outside ,

microbial / bacterial / fungal , cells ;

2 (microbes) lose water and cannot , reproduce /

survive / carry out metabolic reactions / AW ;

3 water moves by osmosis ;

Q7(c)-GCE-Biology -June 2014-F212/01

1 Cannot be implied from references to water potential

gradient

1 ACCEPT reduces beef water potential

1 IGNORE solute potential

1 IGNORE viruses

2 ACCEPT bacteria lose water and die

2 AWARD only in context of microbes dehydrating

2 IGNORE viruses

2 IGNORE beef losing water so microbes cant reproduce

3 ACCEPT in any correct water potential contex


L,M,H

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12(a)(i) 2

A nucleus ;

B chloroplast ;

Q1(a)(i)-GCE-Biology - June 2013-F211/01

Mark the first answer on each prompt line. If the answer

is correct and an additional answer is given that is

incorrect or contradicts the correct answer then = 0 marks

DO NOT CREDIT nuclear envelope / nucleolus

IGNORE chlorophyll

Foundations in Biology; Cell Structure

L,M

12(a)(ii) 2

C mitochondrion

(aerobic) respiration / producing ATP / release

energy ;

D SER / smooth endoplasmic reticulum

transport / production / processing, of, fats /

lipids /

steroids / carbohydrates

Q1(a)(ii)-GCE-Biology - June 2013-F211/01

Mark the first answer on each prompt line. If the answer

is correct and an additional answer is given that is

incorrect or contradicts the correct answer then = 0 marks

DO NOT CREDIT Function of organelle if organelle

identified / named incorrectly (as this would be an incorrect biological statement.

DO NOT CREDIT makes / produces, energy

ACCEPT produces ATP for respiration

IGNORE ref to transport / modification of proteins

DO NOT CREDIT ref production of proteins


L,M

12(b) 2 C / mitochondrion / cristae, too small ;

resolution (of light microscope), not high

(enough)

OR idea of only, 0.2μm / 200nm ;

wavelength of light too long ;

Q1(b)-GCE-Biology - June 2013-F211/01

idea of too small / not big enough important

IGNORE very small

ACCEPT resolution low

IGNORE ref to magnification

for resolution accept any value in range 0.05 - 0.2 μm

IGNORE ref to electron microscope


M,H

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13(a) 1 enzymes ; Q2(a)-GCE-Biology -June 2013-F212/01 IGNORE protein / catalysts

ACCEPT enzymic

Foundations in Biology; Enzymes

L

13(b)(i) 3 1 similar, shape / structure ;

2 example of similarity ;

3 both, will fit into / complementary (shape) to /

bind to / bond to , active site (of alcohol

dehydrogenase ) ;

Q2(b)(i)-GCE-Biology -June 2013-F212/01

1 IGNORE same shape

1 ACCEPT ‘ethanol same shape as part of DEG’

2 IGNORE they contain C, H and O

2 IGNORE the end is the same

2 ACCEPT e.g. they both have OH

2 ACCEPT similar parts identified on diagram if they are

clearly indicating an example of similarity

3 ACCEPT implication of both

3 IGNORE attach / enter

3 IGNORE both will form ESC (with alcohol

dehydrogenase)

Foundations in Biology; Enzymes

L,M,H

13(b)(ii) 3 1 (ethanol) competes with DEG ; ora 2 (when at high(er) concentration) ethanol more

likely to , collide with / bind to / bond to , active site ; ora 3 less , DEG breakdown / toxic product ; ora

Q2(b)(ii)-GCE-Biology -June 2013-F212/01

1 ACCEPT ethanol / DEG , is , a competitive inhibitor

2 ACCEPT ‘ethanol more likely to form ESC’

2 ACCEPT implication of ‘more likely’ from context

2 IGNORE attach / enter

3 ACCEPT DEG product is diluted

3 ACCEPT no DEG breakdown

IGNORE ‘you will drink less of it’

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14(i) 1 code for (one or more) polypeptide(s) ; Q5(d)(i)-GCE-Biology - June 2014-F212/01 ACCEPT protein

IGNORE amino acid sequence

Foundations in Biology; Nucleotides and nucleic acids

L,M,H

14(ii) 5 1 double stranded ;

2 each / both (strands) act as template ;

3 hydrogen bonds , easily , break / form ,

between

bases ;

4 complementary (specified) base , pairing / AW

;

5 purine (only able to) bind to pyrimidine ;

6 (due to) different sizes of purines and

pyrimidines ;

7 hydrogen bonding different between A & T and

C & G

or

3 H bonds between C & G and

2 H bonds between A & T ;

Q5(d)(ii)-GCE-Biology -June 2014-F212/01

AWARD marks from clearly annotated diagram

1 ACCEPT double helix or two , polynucleotides / strands / chains or antiparallel strands

1 IGNORE one old and one new strand

2 IGNORE either

NOTE ‘there are 2 strands which act as templates’ = 2

marks (mp 1 and 2)

3 ACCEPT weak H bonds between bases break

3 IGNORE refs to H bonds , breaking / forming , without

qualification that the bonds are weak or , form / break , easily

4 IGNORE complementary nucleotides unless qualified

with examples of base-pairing

7 ACCEPT names of bases with phonetic spellings

7 DO NOT CREDIT thyamine

7ACCEPT A=T and C≡G without reference to hydrogen

bonds

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15(a)(i) 1 primary structure ; Q1(a)(i)-GCE-Biology -June 2013-F212/01 ACCEPT 1o structure

IGNORE polypeptide


L,M

15(a)(ii) 3 NH2 at one end ;

COOH at opposite end ;

C in centre (of a single amino acid) bonded

(separately) to one R and one H ;

Q1(a)(ii)-GCE-Biology -June 2013-F212/01

If R group not shown as ‘R’ then award max 2 (as general

structure asked for in Q) IGNORE labels

ACCEPT displayed structure of NH2 / HNH

ACCEPT displayed structure of COOH if correct double

bond shown

AWARD only if the candidate has drawn a single ‘amino

acid’ Molecule

H

H2N C COOH

R

© OCR 2016 Page 21


OCR Resources: the small print

OCR’s resources are provided to support the teaching of OCR specifications, but in no way constitute an endorsed teaching method that is required by the Board, and the

decision to use them lies with the individual teacher. Whilst every effort is made to ensure the accuracy of the content, OCR cannot be held responsible for any errors or

omissions within these resources. We update our resources on a regular basis, so please check the OCR website to ensure you have the most up to date version.

© OCR 2016


15(b) 1 strength / toughness / insolubility ; Q1(b)(i)-GCE-Biology -June 2013-F212/01 Mark the first answer. If the answer is correct and an

additional answer is given that is incorrect or contradicts

the correct answer then = 0 marks

ACCEPT strong / tough

IGNORE flexible / inelastic

IGNORE withstand pressure


L,M,H

15(c) 1 transport / AW , of, oxygen / O2 ; Q1(c)(i)-GCE-Biology -June 2013-F212/01 Mark the first answer. If the answer is correct and an

additional answer is given that is incorrect or contradicts

the correct answer then = 0 marks

ACCEPT buffering blood / carrying CO2 / storing oxygen

IGNORE binding oxygen

IGNORE Iron


L,M,H

Total 64

ocr as/a level biology a (h020/h420) - schudio · 2020. 3. 25. · ocr as/a level biology a...

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