1
AQA A-LEVEL BIOLOGY PAPER 2 2026/2027 |
BIOLOGY | 100 VERIFIED Q&A | DETAILED
RATIONALES | PASS GUARANTEED – A+ GRADED
SECTION 1: PHOTOSYNTHESIS & RESPIRATION - Questions 1-20
Q1: Light-Dependent Reaction Site
The student is reviewing photosynthesis. Where do the light-dependent reactions occur?
A. Stroma
B. Thylakoid membranes
C. Inner mitochondrial membrane
D. Cytoplasm
Correct Answer: B
Rationale: The light-dependent reactions occur on the thylakoid membranes of chloroplasts, where
photosystems, electron transport chains, and ATP synthase are located. The stroma is the site of the
light-independent reactions (Calvin cycle). [100% CORRECT]
Q2: Photolysis of Water
The student is reviewing photosynthesis. What is the role of photolysis in the light-dependent
reaction?
A. Produces glucose
B. Splits water into protons, electrons, and oxygen
C. Fixes carbon dioxide
D. Generates ATP only
Correct Answer: B
Rationale: Photolysis is the splitting of water by light energy, producing electrons (replace those lost
by photosystem II), protons (used in chemiosmosis), and oxygen (by-product). [100% CORRECT]
Q3: Chemiosmosis in Chloroplasts
The student is reviewing photosynthesis. How is ATP synthesised during the light-dependent
reaction?
A. Substrate-level phosphorylation
B. Chemiosmosis via ATP synthase
C. Direct transfer from photosystem I
D. Oxidation of NADPH
,2
Correct Answer: B
Rationale: Electrons passed along the electron transport chain pump protons into the thylakoid
space, creating a proton gradient. Protons flow back through ATP synthase, generating ATP by
chemiosmosis. [100% CORRECT]
Q4: Products of Light-Dependent Reaction
The student is reviewing photosynthesis. Which products of the light-dependent reaction are used in
the Calvin cycle?
A. Oxygen and glucose
B. ATP and NADPH
C. ADP and NADP
D. Water and carbon dioxide
Correct Answer: B
Rationale: ATP and NADPH produced in the light-dependent reactions are used in the Calvin cycle to
reduce GP to TP. Oxygen is a by-product, and ADP/NADP are returned to the light-dependent stage.
[100% CORRECT]
Q5: Calvin Cycle – Carbon Fixation
The student is reviewing the Calvin cycle. Which enzyme catalyses the fixation of carbon dioxide?
A. Rubisco
B. ATP synthase
C. Dehydrogenase
D. PEP carboxylase
Correct Answer: A
Rationale: Rubisco (ribulose bisphosphate carboxylase) catalyses the reaction between CO₂ and
RuBP to form two molecules of GP (glycerate-3-phosphate). [100% CORRECT]
Q6: Calvin Cycle – Reduction
The student is reviewing the Calvin cycle. What is the role of NADPH in the Calvin cycle?
A. It provides energy for ATP synthesis
B. It reduces GP to TP
C. It fixes carbon dioxide
D. It regenerates RuBP
Correct Answer: B
Rationale: NADPH (with ATP) reduces glycerate-3-phosphate (GP) to triose phosphate (TP). ATP
provides energy, NADPH provides reducing power. [100% CORRECT]
, 3
Q7: Limiting Factors in Photosynthesis
The student is reviewing limiting factors. Which factor is most likely to limit photosynthesis on a
warm, bright, dry day?
A. Light intensity
B. Carbon dioxide concentration
C. Temperature
D. Water availability
Correct Answer: D
Rationale: On a warm, bright, dry day, stomata may close to reduce water loss (transpiration),
limiting CO₂ uptake. Water availability can also directly limit photosynthesis. Light and temperature
are likely not limiting under these conditions. [100% CORRECT]
Q8: Glycolysis Location
The student is reviewing respiration. Where does glycolysis occur?
A. Mitochondrial matrix
B. Cytoplasm
C. Inner mitochondrial membrane
D. Nucleus
Correct Answer: B
Rationale: Glycolysis occurs in the cytoplasm and does not require oxygen. It converts glucose to
pyruvate, producing ATP and NADH. [100% CORRECT]
Q9: Glycolysis Products
The student is reviewing respiration. What is the net yield of glycolysis per glucose molecule?
A. 2 ATP, 2 NADH, 2 pyruvate
B. 4 ATP, 2 NADH, 2 pyruvate
C. 2 ATP, 4 NADH, 2 pyruvate
D. 36 ATP, 2 NADH, 2 pyruvate
Correct Answer: A
Rationale: Glycolysis uses 2 ATP and produces 4 ATP (net 2), 2 NADH, and 2 pyruvate per glucose.
[100% CORRECT]
Q10: Link Reaction
The student is reviewing respiration. What happens during the link reaction?
A. Pyruvate is converted to acetyl CoA, producing NADH and CO₂
B. Glucose is split into two pyruvate molecules
AQA A-LEVEL BIOLOGY PAPER 2 2026/2027 |
BIOLOGY | 100 VERIFIED Q&A | DETAILED
RATIONALES | PASS GUARANTEED – A+ GRADED
SECTION 1: PHOTOSYNTHESIS & RESPIRATION - Questions 1-20
Q1: Light-Dependent Reaction Site
The student is reviewing photosynthesis. Where do the light-dependent reactions occur?
A. Stroma
B. Thylakoid membranes
C. Inner mitochondrial membrane
D. Cytoplasm
Correct Answer: B
Rationale: The light-dependent reactions occur on the thylakoid membranes of chloroplasts, where
photosystems, electron transport chains, and ATP synthase are located. The stroma is the site of the
light-independent reactions (Calvin cycle). [100% CORRECT]
Q2: Photolysis of Water
The student is reviewing photosynthesis. What is the role of photolysis in the light-dependent
reaction?
A. Produces glucose
B. Splits water into protons, electrons, and oxygen
C. Fixes carbon dioxide
D. Generates ATP only
Correct Answer: B
Rationale: Photolysis is the splitting of water by light energy, producing electrons (replace those lost
by photosystem II), protons (used in chemiosmosis), and oxygen (by-product). [100% CORRECT]
Q3: Chemiosmosis in Chloroplasts
The student is reviewing photosynthesis. How is ATP synthesised during the light-dependent
reaction?
A. Substrate-level phosphorylation
B. Chemiosmosis via ATP synthase
C. Direct transfer from photosystem I
D. Oxidation of NADPH
,2
Correct Answer: B
Rationale: Electrons passed along the electron transport chain pump protons into the thylakoid
space, creating a proton gradient. Protons flow back through ATP synthase, generating ATP by
chemiosmosis. [100% CORRECT]
Q4: Products of Light-Dependent Reaction
The student is reviewing photosynthesis. Which products of the light-dependent reaction are used in
the Calvin cycle?
A. Oxygen and glucose
B. ATP and NADPH
C. ADP and NADP
D. Water and carbon dioxide
Correct Answer: B
Rationale: ATP and NADPH produced in the light-dependent reactions are used in the Calvin cycle to
reduce GP to TP. Oxygen is a by-product, and ADP/NADP are returned to the light-dependent stage.
[100% CORRECT]
Q5: Calvin Cycle – Carbon Fixation
The student is reviewing the Calvin cycle. Which enzyme catalyses the fixation of carbon dioxide?
A. Rubisco
B. ATP synthase
C. Dehydrogenase
D. PEP carboxylase
Correct Answer: A
Rationale: Rubisco (ribulose bisphosphate carboxylase) catalyses the reaction between CO₂ and
RuBP to form two molecules of GP (glycerate-3-phosphate). [100% CORRECT]
Q6: Calvin Cycle – Reduction
The student is reviewing the Calvin cycle. What is the role of NADPH in the Calvin cycle?
A. It provides energy for ATP synthesis
B. It reduces GP to TP
C. It fixes carbon dioxide
D. It regenerates RuBP
Correct Answer: B
Rationale: NADPH (with ATP) reduces glycerate-3-phosphate (GP) to triose phosphate (TP). ATP
provides energy, NADPH provides reducing power. [100% CORRECT]
, 3
Q7: Limiting Factors in Photosynthesis
The student is reviewing limiting factors. Which factor is most likely to limit photosynthesis on a
warm, bright, dry day?
A. Light intensity
B. Carbon dioxide concentration
C. Temperature
D. Water availability
Correct Answer: D
Rationale: On a warm, bright, dry day, stomata may close to reduce water loss (transpiration),
limiting CO₂ uptake. Water availability can also directly limit photosynthesis. Light and temperature
are likely not limiting under these conditions. [100% CORRECT]
Q8: Glycolysis Location
The student is reviewing respiration. Where does glycolysis occur?
A. Mitochondrial matrix
B. Cytoplasm
C. Inner mitochondrial membrane
D. Nucleus
Correct Answer: B
Rationale: Glycolysis occurs in the cytoplasm and does not require oxygen. It converts glucose to
pyruvate, producing ATP and NADH. [100% CORRECT]
Q9: Glycolysis Products
The student is reviewing respiration. What is the net yield of glycolysis per glucose molecule?
A. 2 ATP, 2 NADH, 2 pyruvate
B. 4 ATP, 2 NADH, 2 pyruvate
C. 2 ATP, 4 NADH, 2 pyruvate
D. 36 ATP, 2 NADH, 2 pyruvate
Correct Answer: A
Rationale: Glycolysis uses 2 ATP and produces 4 ATP (net 2), 2 NADH, and 2 pyruvate per glucose.
[100% CORRECT]
Q10: Link Reaction
The student is reviewing respiration. What happens during the link reaction?
A. Pyruvate is converted to acetyl CoA, producing NADH and CO₂
B. Glucose is split into two pyruvate molecules
