AQA A level Biology Revision
Describe how you would use a biochemical test to show that a solution contained a non-
reducing sugar, such as sucrose. [3] - Correct Answers-,first reducing sugars test; boil with dilute
HCl acid then Neutralise with NaHCǑ, add benedict and heat to 95 degrees C brick red ppt
forms if reducing sugar is present
Describe a chemical test you could carry out to show that a piece of coconut contains lipids. [3]
- Correct Answers-(Crush in) ethanol / alcohol; Add (to) water (Order of adding is critical for this
point); Emulsion / white colour
Explain what is meant by a polymer. [1] - Correct Answers-Molecule) made up of many
identical/similar molecules/monomers/ subunits;
Name the reaction which occurs when starch is broken down into maltose. [1] - Correct
Answers-Hydrolysis
What is the formula for lactose? [2] - Correct Answers-C12 ; H22Ō1
Describe how β-glucose molecule differs from a molecule of α-glucose. [1] - Correct Answers-H
at top right end (instead of OH) / OH at bottom (carbon 1)
Show two ways in which the structure of cellulose is different from the structure of starch. [2] -
Correct Answers-Starch 1,4 and 1,6 bonds / branching Cellulose 1,4 bonds / no 1,6 bonds /
straight; starch All glucoses /monomers same way up cellulose Alternate glucoses upside down;
starch Helix / coiled/compact cellulose Straight; Starch monomer Alpha glucose Cellulose
monomer Beta glucose
Describe the structure of starch and explain how its structure is related to its function. [3] -
Correct Answers-Formed from α glucose; Joined by condensation/ by the removal of a water
molecule/ glycosidic bonds; Between (carbons) 1 and 4 (and 1 and 6); Coiled chain; compact;
(Allows) storage of large amount in a small space; Insoluble so has no effect on osmosis/water
potential; Branches; (Allows) rapid breakdown/release of glucose / hydrolysis;
The structure of a phospholipid molecule is different from that of a triglyceride. Describe how.
[2] - Correct Answers-triglyceride has three fatty acids and phospholipid has two; no phosphate
group present in triglyceride but present in phospholipid.
, What is an unsaturated fatty acid? [1] - Correct Answers-Some / two carbons with only one
hydrogen / (double bonds) between carbon atoms / not saturated with hydrogen;
Describe the structure of cellulose and explain how its structure is related to its function. [3] -
Correct Answers-Alternate β-glucose rotated 180o, long straight chains, Many hydrogen bonds
join (polysaccharide) chains/molecules to each other / makes microfibrils / gives tensile
strength;
Which elements are found in proteins? [1] - Correct Answers-Carbon, hydrogen, oxygen,
nitrogen (sometimes sulphur)
Describe how you would use a biochemical test to show that a solution contained protein. [2] -
Correct Answers-Biuret / alkali + copper sulphate; Lilac/purple/mauve/violet;
Which bonds are found in a)Primary structure [1]b)Secondary structure [1] c)Tertiary structure
[2] - Correct Answers-a)Peptide b) Hydrogen (and peptide) c)Ionic, disulphide bridges,
hydrophobic interactions (hydrogen and peptide)
Explain how a change in the primary structure of a globular protein may result in a different
three-dimensional structure. [3] - Correct Answers-Sequence of amino acids changes; tertiary
structure changes/folds in a different way; bonds form in different places (not peptide);
Describe how two-way chromatography is carried out. [2] - Correct Answers-Run
chromatogram then turn through 90/right angle; With a different solvent;
Explain the advantage of using two-way chromatography to separate short polypeptides. [2] -
Correct Answers-Spreads spots/polypeptides out more/ make sure spot only contains one
substance;
Explain how inhibitors affect the rate of enzyme-controlled reactions. [6] - Correct Answers-
Statement about two types, competitive and non-competitive; Competitive: Similar shape to
substrate;Inhibitor can enter/bind with active site (of enzyme);Non-competitive: Affect/bind to
enzyme other than at active site; Distorts shape of active site; Inhibitors: Prevent entry
of/binding of substrate to active site; Therefore fewer/no enzyme-substrate complexes formed;
Describe and explain how an increase in temperature affects the rate of an enzyme controlled
reaction. [5] - Correct Answers-Rate of reaction increases; Increasing temperature increases
rate of movement of molecules/ kinetic energy; Collide more often/substrate enters active site
more often/more enzyme-substrate complexes formed; Up to optimum; Rate of reaction
decreases; High temperatures cause denaturation/loss of tertiary structure/3D structure; By
Describe how you would use a biochemical test to show that a solution contained a non-
reducing sugar, such as sucrose. [3] - Correct Answers-,first reducing sugars test; boil with dilute
HCl acid then Neutralise with NaHCǑ, add benedict and heat to 95 degrees C brick red ppt
forms if reducing sugar is present
Describe a chemical test you could carry out to show that a piece of coconut contains lipids. [3]
- Correct Answers-(Crush in) ethanol / alcohol; Add (to) water (Order of adding is critical for this
point); Emulsion / white colour
Explain what is meant by a polymer. [1] - Correct Answers-Molecule) made up of many
identical/similar molecules/monomers/ subunits;
Name the reaction which occurs when starch is broken down into maltose. [1] - Correct
Answers-Hydrolysis
What is the formula for lactose? [2] - Correct Answers-C12 ; H22Ō1
Describe how β-glucose molecule differs from a molecule of α-glucose. [1] - Correct Answers-H
at top right end (instead of OH) / OH at bottom (carbon 1)
Show two ways in which the structure of cellulose is different from the structure of starch. [2] -
Correct Answers-Starch 1,4 and 1,6 bonds / branching Cellulose 1,4 bonds / no 1,6 bonds /
straight; starch All glucoses /monomers same way up cellulose Alternate glucoses upside down;
starch Helix / coiled/compact cellulose Straight; Starch monomer Alpha glucose Cellulose
monomer Beta glucose
Describe the structure of starch and explain how its structure is related to its function. [3] -
Correct Answers-Formed from α glucose; Joined by condensation/ by the removal of a water
molecule/ glycosidic bonds; Between (carbons) 1 and 4 (and 1 and 6); Coiled chain; compact;
(Allows) storage of large amount in a small space; Insoluble so has no effect on osmosis/water
potential; Branches; (Allows) rapid breakdown/release of glucose / hydrolysis;
The structure of a phospholipid molecule is different from that of a triglyceride. Describe how.
[2] - Correct Answers-triglyceride has three fatty acids and phospholipid has two; no phosphate
group present in triglyceride but present in phospholipid.
, What is an unsaturated fatty acid? [1] - Correct Answers-Some / two carbons with only one
hydrogen / (double bonds) between carbon atoms / not saturated with hydrogen;
Describe the structure of cellulose and explain how its structure is related to its function. [3] -
Correct Answers-Alternate β-glucose rotated 180o, long straight chains, Many hydrogen bonds
join (polysaccharide) chains/molecules to each other / makes microfibrils / gives tensile
strength;
Which elements are found in proteins? [1] - Correct Answers-Carbon, hydrogen, oxygen,
nitrogen (sometimes sulphur)
Describe how you would use a biochemical test to show that a solution contained protein. [2] -
Correct Answers-Biuret / alkali + copper sulphate; Lilac/purple/mauve/violet;
Which bonds are found in a)Primary structure [1]b)Secondary structure [1] c)Tertiary structure
[2] - Correct Answers-a)Peptide b) Hydrogen (and peptide) c)Ionic, disulphide bridges,
hydrophobic interactions (hydrogen and peptide)
Explain how a change in the primary structure of a globular protein may result in a different
three-dimensional structure. [3] - Correct Answers-Sequence of amino acids changes; tertiary
structure changes/folds in a different way; bonds form in different places (not peptide);
Describe how two-way chromatography is carried out. [2] - Correct Answers-Run
chromatogram then turn through 90/right angle; With a different solvent;
Explain the advantage of using two-way chromatography to separate short polypeptides. [2] -
Correct Answers-Spreads spots/polypeptides out more/ make sure spot only contains one
substance;
Explain how inhibitors affect the rate of enzyme-controlled reactions. [6] - Correct Answers-
Statement about two types, competitive and non-competitive; Competitive: Similar shape to
substrate;Inhibitor can enter/bind with active site (of enzyme);Non-competitive: Affect/bind to
enzyme other than at active site; Distorts shape of active site; Inhibitors: Prevent entry
of/binding of substrate to active site; Therefore fewer/no enzyme-substrate complexes formed;
Describe and explain how an increase in temperature affects the rate of an enzyme controlled
reaction. [5] - Correct Answers-Rate of reaction increases; Increasing temperature increases
rate of movement of molecules/ kinetic energy; Collide more often/substrate enters active site
more often/more enzyme-substrate complexes formed; Up to optimum; Rate of reaction
decreases; High temperatures cause denaturation/loss of tertiary structure/3D structure; By
