macromolecules chapter 5. macromolecules large complex molecules carbohydrates, proteins, lipids...
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Macromolecules
Chapter 5
Macromolecules
Large complex molecules Carbohydrates, proteins, lipids &
nucleic acids
Macromolecules
Polymer Large molecule Carboydrates, proteins, nucleic
acids Monomers Smaller repeating units Build polymers
Macromolecules
Monomers are connected by a dehydration reaction
Condensation reaction
Fig. 5-2a
Dehydration removes a watermolecule, forming a new bond
Short polymer Unlinked monomer
Longer polymer
Dehydration reaction in the synthesis of a polymer
HO
HO
HO
H2O
H
HH
4321
1 2 3
(a)
Macromolecules
Polymers are broken apart into monomers by hydrolysis
Bonds are broken by adding water
Fig. 5-2b
Hydrolysis adds a watermolecule, breaking a bond
Hydrolysis of a polymer
HO
HO HO
H2O
H
H
H321
1 2 3 4
(b)
Carbohydrates
Simple sugars to complex polymers
Stored energy Structure
Carbohydrates
Monosaccharides Single sugar
– Glucose, fructose, galactose Molecules contain carbon, hydrogen &
oxygen in a 1:2:1 ratio CH2O End in –ose Aldose: aldehyde sugar Ketose: ketone sugar
Fig. 5-3a
Ald
ose
s
Glyceraldehyde
Ribose
Glucose Galactose
Hexoses (C6H12O6)Pentoses (C5H10O5)Trioses (C3H6O3)
Fig. 5-3b
Ket
ose
s
Dihydroxyacetone
Ribulose
Fructose
Hexoses (C6H12O6)Pentoses (C5H10O5)Trioses (C3H6O3)
Carbohydrates
Dissaccharides Two monosaccharides combined Glycoside linkage: Covalent bond between two sugars Sucrose (glucose & fructose) Maltose (glucose & glucose) Lactose (glucose & galactose)
Fig. 5-5
(b) Dehydration reaction in the synthesis of sucrose
Glucose Fructose Sucrose
MaltoseGlucoseGlucose
(a) Dehydration reaction in the synthesis of maltose
1–4glycosidic
linkage
1–2glycosidic
linkage
Carbohydrates
Polysaccharides Many monosaccharides combined Starch (plant), glycogen (animal),
cellulose (plant), chitin
Fig. 5-7
(a) and glucose ring structures
Glucose Glucose
(b) Starch: 1–4 linkage of glucose monomers (b) Cellulose: 1–4 linkage of glucose monomers
Fig. 5-10
The structureof the chitinmonomer.
(a) (b) (c)Chitin forms theexoskeleton ofarthropods.
Chitin is used to makea strong and flexiblesurgical thread.
Lipids
Insoluble in water– Hydrophobic
Store energy Make membranes
Lipids
Fats– Unsaturated– Saturated
Phospholipids– Glycerol, phosphate, fatty acid
Steroids
Fats
Glycerol and fatty acids Triglyceride 3 fatty acids attached to a glycerol
Fatty acid(palmitic acid)
(a) Dehydration reaction in the synthesis of a fat
Glycerol
Fig. 5-11b
(b) Fat molecule (triacylglycerol)
Ester linkage
Fig. 5-12
Structuralformula of asaturated fatmolecule
Stearic acid, asaturated fattyacid
(a) Saturated fat
Structural formulaof an unsaturatedfat molecule
Oleic acid, anunsaturatedfatty acid
(b) Unsaturated fat
cis doublebond causesbending
Phospholipids
Cell membrane Tails are hydrophobic Hydrophilic head
Fig. 5-14
Hydrophilichead
Hydrophobictail WATER
WATER
Steroids
Steroids
Proteins
Amino acids Building blocks of proteins 20 different amino acids Peptide bond Polypeptide
Peptidebond
Fig. 5-18
Amino end(N-terminus)
Peptidebond
Side chains
Backbone
Carboxyl end(C-terminus)
(a)
(b)
Fig. 5-17Nonpolar
Glycine(Gly or G)
Alanine(Ala or A)
Valine(Val or V)
Leucine(Leu or L)
Isoleucine(Ile or I)
Methionine(Met or M)
Phenylalanine(Phe or F)
Trypotphan(Trp or W)
Proline(Pro or P)
Polar
Serine(Ser or S)
Threonine(Thr or T)
Cysteine(Cys or C)
Tyrosine(Tyr or Y)
Asparagine(Asn or N)
Glutamine(Gln or Q)
Electricallycharged
Acidic Basic
Aspartic acid(Asp or D)
Glutamic acid(Glu or E)
Lysine(Lys or K)
Arginine(Arg or R)
Histidine(His or H)
Protein Function
Enzyme catalysis Defense Transport Support Motion Regulation Storage
Protein structure
Primary Secondary Tertiary Quaternary
Primary Structure
Sequence of amino acids
Secondary Structure
Hydrogen bonds between amino acids
Pleats or helix
Tertiary structure
Attraction between side chains Hydrophobic interaction Disulfide bridges Ionic bonds Hydrogen bonds
Quaternary structure
Two or more polypeptide chains aggregate
Sickle cell anemia
Fig. 5-22
Primarystructure
Secondaryand tertiarystructures
Quaternarystructure
Normalhemoglobin(top view)
Primarystructure
Secondaryand tertiarystructures
Quaternarystructure
Function Function
subunit
Molecules donot associatewith oneanother; eachcarries oxygen.
Red bloodcell shape
Normal red bloodcells are full ofindividualhemoglobinmoledules, eachcarrying oxygen.
10 µm
Normal hemoglobin
1 2 3 4 5 6 7
Val His Leu Thr Pro Glu Glu
Red bloodcell shape
subunit
Exposedhydrophobicregion
Sickle-cellhemoglobin
Moleculesinteract withone another andcrystallize intoa fiber; capacityto carry oxygenis greatly reduced.
Fibers of abnormalhemoglobin deformred blood cell intosickle shape.
10 µm
Sickle-cell hemoglobin
GluProThrLeuHisVal Val
1 2 3 4 5 6 7
Structure
Denaturation: Alter, unravel shape of protein Temperature, pH, salt Chaperonins: Proteins that help with structure
Nucleic Acids
DNA and RNA Transfer & store genetic
information Nucleotides are the subunits Nitrogenous base 5 carbon sugar Phosphate group
Nucleic Acids
Pyrimidines Cytosine, thymine and uracil Single carbon ring Purines Adenine, guanine Double ring structure
Nitrogenous Bases
Fig. 5-27c-1
(c) Nucleoside components: nitrogenous bases
Purines
Guanine (G)Adenine (A)
Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA)
Nitrogenous bases
Pyrimidines
Fig. 5-27c-2
Ribose (in RNA)Deoxyribose (in DNA)
Sugars
(c) Nucleoside components: sugars
DNA
Double helix Sugar-phosphate backbone is on the
outside of helix Run in opposite direction Antiparallel Base pairs held together by hydrogen
bonds Adenine-thymine (uracil) Cytosine-guanine
DNA
DNA
Fig. 5-28
Sugar-phosphatebackbones
3' end
3' end
3' end
3' end
5' end
5' end
5' end
5' end
Base pair (joined byhydrogen bonding)
Old strands
Newstrands
Nucleotideabout to beadded to anew strand