OH PO₄
AQA A-LEVEL BIOLOGY 7402
Biological
Molecules A
T
T
A
Question-led revision guide C G
G C
Learn the content. Think like the mark scheme.
A T
G C
T A
Inside: complete specification coverage, C G
original exam-style questions,
examiner-style marking points, required A T
practical skills, data analysis and
high-value diagrams.
INDEPENDENT REVISION RESOURCE
Not endorsed by AQA. All practice questions and diagrams are original.
BIOLOGY 3.1
, START HERE
How to use this guide
This guide is built around one principle: you do not truly know a topic until you can use it in an unfamiliar
question. Every section moves from core knowledge to application and then to precise marking points.
1 Diagnose 2 Learn
Attempt the question before opening the Use the explanation and diagram to repair the
marking points. Circle the command word and exact gap the question exposed.
underline the context.
4 Rebuild
3 Mark
Rewrite the answer from memory using fewer,
Award one mark only when your wording more precise sentences. Return 48 hours later.
contains the full biological link. Do not credit
your intention.
The three-pass method
Pass 1 - recall: no notes. Pass 2 - repair: add missing marking points in a different colour. Pass 3 -
transfer: answer a new context question without copying the model.
Symbols used throughout
Q Original exam-style question RP Required practical skill
MP A distinct marking point AO2 Apply knowledge to context
! Common wording trap AO3 Analyse or evaluate
AQA A-level Biology 7402 | Biological molecules 2
, CHECKLIST
Specification map
Tick each row only when you can define it, draw it and answer an unfamiliar question about it. This map
follows AQA section 3.1.
Section You must be able to... ✓
3.1.1 Explain monomers, polymers, condensation and hydrolysis □
3.1.2 Compare carbohydrates; link starch, glycogen and cellulose structure to function; perform food tests □
Recognise triglycerides, phospholipids and saturated or unsaturated fatty acids; explain properties; emulsion
3.1.3 □
test
3.1.4.1 Build proteins from amino acids; explain peptide bonds and all four levels of structure; Biuret test □
3.1.4.2 Explain induced fit, activation energy, specificity, factors affecting rate and both inhibitor types □
RP1 Plan an enzyme investigation; control variables; calculate uncertainty and initial rate □
3.1.5.1 Compare DNA and RNA; draw a nucleotide; explain phosphodiester and hydrogen bonds □
3.1.5.2 Explain semi-conservative DNA replication and roles of helicase and polymerase □
3.1.6 Explain ATP structure, hydrolysis, phosphorylation and resynthesis □
3.1.7 Link water's properties to biological functions □
3.1.8 Apply roles of H⁺, Fe²⁺, Na⁺ and phosphate ions □
Coverage note: The AQA overview itself is contextual and not directly assessed, but the content listed in the left column of the
specification can be assessed in written papers.
AQA A-level Biology 7402 | Biological molecules 3
, EXAM TECHNIQUE
How AQA marking works
One mark = one complete idea
A biological keyword alone is rarely enough. The mark usually comes from a relationship: feature →
mechanism → consequence. For example, 'cellulose is strong' is weaker than 'many hydrogen bonds
between adjacent chains form microfibrils with high tensile strength'.
Command words Mark-scheme habits
Describe: give an accurate account of what happens or Name the molecule or structure instead of writing 'it'.
what the data show.
Use comparative language: more, less, higher, lower,
Explain: connect a cause to its biological consequence. faster.
Compare: make paired statements using both items. Quote data with units when a figure or table is supplied.
Suggest: apply valid biology to information you may not Do not add contradictory statements to a list answer.
have seen before.
For calculations, show substitution and keep full values until
Evaluate: use evidence for and against, then judge the final rounding.
limitations or strength.
QUESTION 0.1 [2 marks]
A student writes: 'A higher temperature makes the enzyme work better because
particles move more.' Improve this into an answer that would gain two marks below
the optimum temperature.
MARKING POINTS
1 Molecules have more kinetic energy, so enzyme and substrate collide more frequently.
2 More successful collisions form more enzyme-substrate complexes per unit time, increasing rate.
Trap: 'works better' does not name the measured outcome. State that the rate increases.
AQA A-level Biology 7402 | Biological molecules 4
AQA A-LEVEL BIOLOGY 7402
Biological
Molecules A
T
T
A
Question-led revision guide C G
G C
Learn the content. Think like the mark scheme.
A T
G C
T A
Inside: complete specification coverage, C G
original exam-style questions,
examiner-style marking points, required A T
practical skills, data analysis and
high-value diagrams.
INDEPENDENT REVISION RESOURCE
Not endorsed by AQA. All practice questions and diagrams are original.
BIOLOGY 3.1
, START HERE
How to use this guide
This guide is built around one principle: you do not truly know a topic until you can use it in an unfamiliar
question. Every section moves from core knowledge to application and then to precise marking points.
1 Diagnose 2 Learn
Attempt the question before opening the Use the explanation and diagram to repair the
marking points. Circle the command word and exact gap the question exposed.
underline the context.
4 Rebuild
3 Mark
Rewrite the answer from memory using fewer,
Award one mark only when your wording more precise sentences. Return 48 hours later.
contains the full biological link. Do not credit
your intention.
The three-pass method
Pass 1 - recall: no notes. Pass 2 - repair: add missing marking points in a different colour. Pass 3 -
transfer: answer a new context question without copying the model.
Symbols used throughout
Q Original exam-style question RP Required practical skill
MP A distinct marking point AO2 Apply knowledge to context
! Common wording trap AO3 Analyse or evaluate
AQA A-level Biology 7402 | Biological molecules 2
, CHECKLIST
Specification map
Tick each row only when you can define it, draw it and answer an unfamiliar question about it. This map
follows AQA section 3.1.
Section You must be able to... ✓
3.1.1 Explain monomers, polymers, condensation and hydrolysis □
3.1.2 Compare carbohydrates; link starch, glycogen and cellulose structure to function; perform food tests □
Recognise triglycerides, phospholipids and saturated or unsaturated fatty acids; explain properties; emulsion
3.1.3 □
test
3.1.4.1 Build proteins from amino acids; explain peptide bonds and all four levels of structure; Biuret test □
3.1.4.2 Explain induced fit, activation energy, specificity, factors affecting rate and both inhibitor types □
RP1 Plan an enzyme investigation; control variables; calculate uncertainty and initial rate □
3.1.5.1 Compare DNA and RNA; draw a nucleotide; explain phosphodiester and hydrogen bonds □
3.1.5.2 Explain semi-conservative DNA replication and roles of helicase and polymerase □
3.1.6 Explain ATP structure, hydrolysis, phosphorylation and resynthesis □
3.1.7 Link water's properties to biological functions □
3.1.8 Apply roles of H⁺, Fe²⁺, Na⁺ and phosphate ions □
Coverage note: The AQA overview itself is contextual and not directly assessed, but the content listed in the left column of the
specification can be assessed in written papers.
AQA A-level Biology 7402 | Biological molecules 3
, EXAM TECHNIQUE
How AQA marking works
One mark = one complete idea
A biological keyword alone is rarely enough. The mark usually comes from a relationship: feature →
mechanism → consequence. For example, 'cellulose is strong' is weaker than 'many hydrogen bonds
between adjacent chains form microfibrils with high tensile strength'.
Command words Mark-scheme habits
Describe: give an accurate account of what happens or Name the molecule or structure instead of writing 'it'.
what the data show.
Use comparative language: more, less, higher, lower,
Explain: connect a cause to its biological consequence. faster.
Compare: make paired statements using both items. Quote data with units when a figure or table is supplied.
Suggest: apply valid biology to information you may not Do not add contradictory statements to a list answer.
have seen before.
For calculations, show substitution and keep full values until
Evaluate: use evidence for and against, then judge the final rounding.
limitations or strength.
QUESTION 0.1 [2 marks]
A student writes: 'A higher temperature makes the enzyme work better because
particles move more.' Improve this into an answer that would gain two marks below
the optimum temperature.
MARKING POINTS
1 Molecules have more kinetic energy, so enzyme and substrate collide more frequently.
2 More successful collisions form more enzyme-substrate complexes per unit time, increasing rate.
Trap: 'works better' does not name the measured outcome. State that the rate increases.
AQA A-level Biology 7402 | Biological molecules 4
