AQA A-LEVEL BIOLOGY
Biology
A-Level Questions That
Seem Easy But Are
TRICKY
& How to Answer Them
Full model answers · Why students get them wrong · Examiner tips
30 8 50+ AQA
Pages Topics Questions Spec
Personal revision use · Year 12 & 13 · AQA Specification A
,AQA A-Level Biology | Tricky Questions & How to Answer Them 2
Contents
# Chapter Page
1 Biological Molecules — the ones that look easy 4
2 Cell Structure & Microscopy Traps 7
3 Enzymes — where precision matters most 10
4 Cell Transport & the Membrane 13
5 DNA, Protein Synthesis & Genetics 16
6 Respiration & Photosynthesis 19
7 Evolution, Biodiversity & Classification 23
8 Ecology & Ecosystems 26
— Revision Checklist 29
— The Trickiest Traps: Final Summary 30
Every question in this guide has caught out students who felt confident going into the exam. They
are not hard questions — they just have common traps: a missing key word, a misunderstood
definition, or an answer that sounds right but loses the mark. For each question you will find
exactly what makes it tricky, a model answer, and an examiner tip pointing to the precise words
that unlock marks on AQA mark schemes.
AQA A-Level Biology Revision Guide Look closer · Think harder · Score higher
, AQA A-Level Biology | Tricky Questions & How to Answer Them 3
CHAPTER 1
Biological Molecules
These questions use familiar terms — glucose, protein, hydrogen bonds — but the marks go to
students who are exact. 'It stores energy' scores zero. 'It releases more energy per gram because
it has more C-H bonds' scores the mark.
Key Terms
Condensation reaction Joins two molecules with a covalent bond and releases one water molecule.
Hydrolysis Breaks a covalent bond in a polymer by adding water.
Glycosidic bond Covalent bond between two monosaccharides, formed by condensation.
Peptide bond Covalent bond between two amino acids, formed between the amino group of one
and the carboxyl group of another.
Denaturation Irreversible change in the 3D shape of a protein caused by disruption of bonds
maintaining tertiary/quaternary structure.
Hydrogen bond A weak electrostatic attraction — individually weak but collectively very important in
water, DNA, and protein structure.
■ WHY THIS IS
Students forget to mention polarity — they just write 'it dissolves things'.
TRICKY
Q1 [3 marks] Explain why water is described as a 'good solvent'.
✔ MODEL Water molecules are polar — the oxygen atom is slightly negative (δ−) and the
ANSWER hydrogen atoms are slightly positive (δ+). Ionic substances (e.g. NaCl) dissolve
because water molecules are attracted to and surround the charged ions, pulling them
apart. Polar molecules (e.g. glucose) also dissolve because their charged regions
interact with the polar water molecules. Non-polar molecules do not dissolve in water
because they cannot interact with the polar water molecules.
★ EXAMINER The word POLAR must appear. Stating that water molecules surround ions is usually a separate
TIP mark. Saying 'it dissolves many substances' alone scores zero.
■ WHY THIS IS Students agree with the statement because both ARE made of alpha-glucose — they miss the
TRICKY structural differences that give different properties.
A student says: 'Starch and glycogen are both made of alpha-glucose, so they
Q2 [4 marks]
must have the same properties.' Evaluate this statement.
AQA A-Level Biology Revision Guide Look closer · Think harder · Score higher
Biology
A-Level Questions That
Seem Easy But Are
TRICKY
& How to Answer Them
Full model answers · Why students get them wrong · Examiner tips
30 8 50+ AQA
Pages Topics Questions Spec
Personal revision use · Year 12 & 13 · AQA Specification A
,AQA A-Level Biology | Tricky Questions & How to Answer Them 2
Contents
# Chapter Page
1 Biological Molecules — the ones that look easy 4
2 Cell Structure & Microscopy Traps 7
3 Enzymes — where precision matters most 10
4 Cell Transport & the Membrane 13
5 DNA, Protein Synthesis & Genetics 16
6 Respiration & Photosynthesis 19
7 Evolution, Biodiversity & Classification 23
8 Ecology & Ecosystems 26
— Revision Checklist 29
— The Trickiest Traps: Final Summary 30
Every question in this guide has caught out students who felt confident going into the exam. They
are not hard questions — they just have common traps: a missing key word, a misunderstood
definition, or an answer that sounds right but loses the mark. For each question you will find
exactly what makes it tricky, a model answer, and an examiner tip pointing to the precise words
that unlock marks on AQA mark schemes.
AQA A-Level Biology Revision Guide Look closer · Think harder · Score higher
, AQA A-Level Biology | Tricky Questions & How to Answer Them 3
CHAPTER 1
Biological Molecules
These questions use familiar terms — glucose, protein, hydrogen bonds — but the marks go to
students who are exact. 'It stores energy' scores zero. 'It releases more energy per gram because
it has more C-H bonds' scores the mark.
Key Terms
Condensation reaction Joins two molecules with a covalent bond and releases one water molecule.
Hydrolysis Breaks a covalent bond in a polymer by adding water.
Glycosidic bond Covalent bond between two monosaccharides, formed by condensation.
Peptide bond Covalent bond between two amino acids, formed between the amino group of one
and the carboxyl group of another.
Denaturation Irreversible change in the 3D shape of a protein caused by disruption of bonds
maintaining tertiary/quaternary structure.
Hydrogen bond A weak electrostatic attraction — individually weak but collectively very important in
water, DNA, and protein structure.
■ WHY THIS IS
Students forget to mention polarity — they just write 'it dissolves things'.
TRICKY
Q1 [3 marks] Explain why water is described as a 'good solvent'.
✔ MODEL Water molecules are polar — the oxygen atom is slightly negative (δ−) and the
ANSWER hydrogen atoms are slightly positive (δ+). Ionic substances (e.g. NaCl) dissolve
because water molecules are attracted to and surround the charged ions, pulling them
apart. Polar molecules (e.g. glucose) also dissolve because their charged regions
interact with the polar water molecules. Non-polar molecules do not dissolve in water
because they cannot interact with the polar water molecules.
★ EXAMINER The word POLAR must appear. Stating that water molecules surround ions is usually a separate
TIP mark. Saying 'it dissolves many substances' alone scores zero.
■ WHY THIS IS Students agree with the statement because both ARE made of alpha-glucose — they miss the
TRICKY structural differences that give different properties.
A student says: 'Starch and glycogen are both made of alpha-glucose, so they
Q2 [4 marks]
must have the same properties.' Evaluate this statement.
AQA A-Level Biology Revision Guide Look closer · Think harder · Score higher
