AQA BIOLOGY A LEVEL 7402 PAPER 1 EXAM
COMPLETE QUESTION PAPER
◉ Describe a chemical test you could carry out to show that a piece
of coconut contains lipids. [3] Answer: (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] Answer: Molecule) made
up of many identical/similar molecules/monomers/ subunits;
◉ Name the reaction which occurs when starch is broken down into
maltose. [1] Answer: Hydrolysis
◉ What is the formula for lactose? [2] Answer: C12 ; H22O1
◉ Describe how β-glucose molecule differs from a molecule of α-
glucose. [1] Answer: 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] Answer: 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] Answer: 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] Answer: 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] Answer: 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] Answer: 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] Answer: Carbon,
hydrogen, oxygen, nitrogen (sometimes sulphur)
◉ Describe how you would use a biochemical test to show that a
solution contained protein. [2] Answer: 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] Answer: 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]
Answer: 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]
Answer: 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] Answer: Spreads
COMPLETE QUESTION PAPER
◉ Describe a chemical test you could carry out to show that a piece
of coconut contains lipids. [3] Answer: (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] Answer: Molecule) made
up of many identical/similar molecules/monomers/ subunits;
◉ Name the reaction which occurs when starch is broken down into
maltose. [1] Answer: Hydrolysis
◉ What is the formula for lactose? [2] Answer: C12 ; H22O1
◉ Describe how β-glucose molecule differs from a molecule of α-
glucose. [1] Answer: 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] Answer: 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] Answer: 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] Answer: 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] Answer: 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] Answer: 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] Answer: Carbon,
hydrogen, oxygen, nitrogen (sometimes sulphur)
◉ Describe how you would use a biochemical test to show that a
solution contained protein. [2] Answer: 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] Answer: 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]
Answer: 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]
Answer: 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] Answer: Spreads
