AQA A-LEVEL BIOLOGY (7402/1) PAPER 1 MARK SCHEME 2021 SPECIMEN V1
Core Domains
- Cellular structure and organisation
- Biological molecules and metabolism
- Genetics and inheritance
- Physiology of organisms
- Ecology and conservation
- Evolutionary theory and speciation
- Experimental design and data analysis
- Bioethics and regulatory compliance
Introduction
This examination assesses a candidate’s understanding of foundational and advanced concepts in biology, evaluating knowledge, application, and
analysis. Questions test factual recall, interpretation of experimental data, and the application of biological principles to real-world professional
contexts. The paper uses multiple-choice and scenario-based items designed to measure decision-making, problem-solving, and integration of
ethics and regulatory considerations. Candidates should demonstrate accurate reasoning, familiarity with laboratory practice, and the ability to
apply theory to practical and policy-related situations.
Section One: Questions 1–100
1. The structure responsible for protein synthesis in a eukaryotic cell is the:
A. Mitochondrion
B. Golgi apparatus
🟢 C. Ribosome
D. Lysosome
🔴 RATIONALE: Ribosomes are the cellular organelles where translation occurs, assembling amino acids into polypeptides based on mRNA
templates.
2. Which macromolecule is composed of nucleotide monomers?
A. Polypeptides
🟢 B. Nucleic acids
C. Polysaccharides
D. Lipids
, 🔴 RATIONALE: Nucleic acids (DNA and RNA) are polymers made from nucleotide monomers, each with a sugar, phosphate, and base.
3. In enzyme kinetics, increasing substrate concentration while keeping enzyme constant will:
A. Decrease Vmax
B. Decrease Km
C. Increase enzyme concentration
🟢 D. Approach Vmax asymptotically
🔴 RATIONALE: As substrate increases, reaction rate approaches the maximum velocity (Vmax) limited by enzyme availability.
4. A mutation that changes one amino acid to another with similar properties is called:
A. Nonsense mutation
B. Frameshift mutation
🟢 C. Missense conservative mutation
D. Silent mutation
🔴 RATIONALE: A missense conservative mutation substitutes an amino acid with similar chemical properties, often preserving function.
5. Which process directly produces ATP in mitochondria?
A. Glycolysis
🟢 B. Oxidative phosphorylation
C. Fermentation
D. Calvin cycle
🔴 RATIONALE: Oxidative phosphorylation uses the electron transport chain and chemiosmosis in mitochondria to generate the majority of ATP.
6. Hardy-Weinberg equilibrium assumes:
A. High mutation rate
🟢 B. No gene flow, infinite population, random mating, no selection
C. Strong selection pressure
D. Non-random mating
🔴 RATIONALE: Hardy-Weinberg describes allele frequencies remaining constant under assumptions including no selection, mutation, migration,
infinite size, and random mating.
, 7. In PCR, the role of primers is to:
A. Digest template DNA
🟢 B. Provide starting points for DNA synthesis
C. Replace nucleotides
D. Separate DNA strands
🔴 RATIONALE: Primers anneal to target sequences and provide a free 3' hydroxyl group for DNA polymerase to extend.
8. The primary regulatory molecule for blood glucose homeostasis after a high-carbohydrate meal is:
🟢 A. Insulin
B. Glucagon
C. Cortisol
D. Adrenaline
🔴 RATIONALE: Insulin is secreted in response to elevated blood glucose and promotes uptake and storage of glucose, lowering blood sugar.
9. Osmosis is best defined as:
A. Active transport of solutes across a membrane
🟢 B. Passive movement of water across a selectively permeable membrane from low solute to high solute
C. Diffusion of solutes down their concentration gradient
D. Endocytosis of fluid
🔴 RATIONALE: Osmosis specifically describes water movement to equalize solute concentrations across a membrane.
0. A double-blind clinical trial design primarily reduces:
A. Sampling error
🟢 B. Observer and participant bias
C. Genetic variability
D. Environmental confounding
🔴 RATIONALE: Double-blind designs prevent participants and researchers from knowing treatment allocation, minimizing bias in outcomes
assessment.
1. Which cell cycle checkpoint ensures DNA is fully replicated before mitosis?
A. G1 checkpoint
🟢 B. G2 checkpoint
C. Spindle checkpoint
D. Cytokinesis checkpoint
Core Domains
- Cellular structure and organisation
- Biological molecules and metabolism
- Genetics and inheritance
- Physiology of organisms
- Ecology and conservation
- Evolutionary theory and speciation
- Experimental design and data analysis
- Bioethics and regulatory compliance
Introduction
This examination assesses a candidate’s understanding of foundational and advanced concepts in biology, evaluating knowledge, application, and
analysis. Questions test factual recall, interpretation of experimental data, and the application of biological principles to real-world professional
contexts. The paper uses multiple-choice and scenario-based items designed to measure decision-making, problem-solving, and integration of
ethics and regulatory considerations. Candidates should demonstrate accurate reasoning, familiarity with laboratory practice, and the ability to
apply theory to practical and policy-related situations.
Section One: Questions 1–100
1. The structure responsible for protein synthesis in a eukaryotic cell is the:
A. Mitochondrion
B. Golgi apparatus
🟢 C. Ribosome
D. Lysosome
🔴 RATIONALE: Ribosomes are the cellular organelles where translation occurs, assembling amino acids into polypeptides based on mRNA
templates.
2. Which macromolecule is composed of nucleotide monomers?
A. Polypeptides
🟢 B. Nucleic acids
C. Polysaccharides
D. Lipids
, 🔴 RATIONALE: Nucleic acids (DNA and RNA) are polymers made from nucleotide monomers, each with a sugar, phosphate, and base.
3. In enzyme kinetics, increasing substrate concentration while keeping enzyme constant will:
A. Decrease Vmax
B. Decrease Km
C. Increase enzyme concentration
🟢 D. Approach Vmax asymptotically
🔴 RATIONALE: As substrate increases, reaction rate approaches the maximum velocity (Vmax) limited by enzyme availability.
4. A mutation that changes one amino acid to another with similar properties is called:
A. Nonsense mutation
B. Frameshift mutation
🟢 C. Missense conservative mutation
D. Silent mutation
🔴 RATIONALE: A missense conservative mutation substitutes an amino acid with similar chemical properties, often preserving function.
5. Which process directly produces ATP in mitochondria?
A. Glycolysis
🟢 B. Oxidative phosphorylation
C. Fermentation
D. Calvin cycle
🔴 RATIONALE: Oxidative phosphorylation uses the electron transport chain and chemiosmosis in mitochondria to generate the majority of ATP.
6. Hardy-Weinberg equilibrium assumes:
A. High mutation rate
🟢 B. No gene flow, infinite population, random mating, no selection
C. Strong selection pressure
D. Non-random mating
🔴 RATIONALE: Hardy-Weinberg describes allele frequencies remaining constant under assumptions including no selection, mutation, migration,
infinite size, and random mating.
, 7. In PCR, the role of primers is to:
A. Digest template DNA
🟢 B. Provide starting points for DNA synthesis
C. Replace nucleotides
D. Separate DNA strands
🔴 RATIONALE: Primers anneal to target sequences and provide a free 3' hydroxyl group for DNA polymerase to extend.
8. The primary regulatory molecule for blood glucose homeostasis after a high-carbohydrate meal is:
🟢 A. Insulin
B. Glucagon
C. Cortisol
D. Adrenaline
🔴 RATIONALE: Insulin is secreted in response to elevated blood glucose and promotes uptake and storage of glucose, lowering blood sugar.
9. Osmosis is best defined as:
A. Active transport of solutes across a membrane
🟢 B. Passive movement of water across a selectively permeable membrane from low solute to high solute
C. Diffusion of solutes down their concentration gradient
D. Endocytosis of fluid
🔴 RATIONALE: Osmosis specifically describes water movement to equalize solute concentrations across a membrane.
0. A double-blind clinical trial design primarily reduces:
A. Sampling error
🟢 B. Observer and participant bias
C. Genetic variability
D. Environmental confounding
🔴 RATIONALE: Double-blind designs prevent participants and researchers from knowing treatment allocation, minimizing bias in outcomes
assessment.
1. Which cell cycle checkpoint ensures DNA is fully replicated before mitosis?
A. G1 checkpoint
🟢 B. G2 checkpoint
C. Spindle checkpoint
D. Cytokinesis checkpoint
