AQA A-Level Biology sample questions and answers (7402)
Guide overview All 8 topics Sample questions Papers and weighting Look inside Questions and answers
40 sample questions and answers
Taken from every topic of AQA A-Level Biology, specification 7402. The full guide has 1,977.
Paper 1, Paper 3
Biological Molecules
272 questions in the guide, across 22 subtopics. More from this topic
-
Monomers, polymers, condensation and hydrolysis
What monomers are joined together to form proteins?
Show the answer
Amino acids. -
Alpha and beta glucose, amylose and amylopectin
Name the unbranched polysaccharide component of starch.
Show the answer
Amylose -
Triglycerides, fatty acids and phospholipid structure
What type of chemical bond forms when glycerol reacts with a fatty acid?
Show the answer
An ester bond. -
The general structure of amino acids
What is the chemical formula of the carboxyl group in an amino acid?
Show the answer
COOH -
Activation energy, induced fit and enzyme specificity
How does the induced-fit model describe the interaction between the active site and substrate during binding?
Show the answer
The active site moulds around the substrate.
Paper 1, Paper 3
Cells
313 questions in the guide, across 24 subtopics. More from this topic
-
Cell-surface membrane, nucleus and mitochondria
What are chromosomes composed of?
Show the answer
Linear DNA bound to proteins. -
Cell specialisation, levels of organisation and organelle roles
What is the correct sequence of organisation from cells to organ systems?
Show the answer
Specialised cells → tissues → organs → organ systems. -
Scanning electron microscopes, magnification and graticules
Are electron microscope images naturally coloured?
Show the answer
No, images are produced in black and white; colour is added artificially. -
The cell cycle, interphase and the stages of mitosis
What happens during prophase of mitosis?
Show the answer
Chromosomes condense and become visible, the nuclear envelope breaks down, and spindle fibres begin to form. -
Mitotic index, mitosis stages and size calculations
What is cytokinesis and when does it occur?
Show the answer
Cytokinesis is the division of the cytoplasm to form two separate daughter cells; it occurs after telophase.
Paper 1, Paper 3
Organisms Exchange Substances with Their Environment
282 questions in the guide, across 19 subtopics. More from this topic
-
Surface area to volume ratio, metabolic rate and calculations
What do organisms with higher metabolic rates require in terms of exchange?
Show the answer
A greater rate of exchange of materials such as oxygen, carbon dioxide, nutrients and waste products. -
Leaf gas exchange, insect water loss and xerophytes
Describe the diffusion pathway for gases in a dicotyledonous leaf.
Show the answer
Gases diffuse through stomata into air spaces in the mesophyll, then to the photosynthesising cells. -
Inspiration, expiration and pulmonary ventilation rate
What happens to the diaphragm during expiration at rest?
Show the answer
It relaxes and returns to its domed shape. -
Digestion of carbohydrates and lipids
Where are membrane-bound disaccharidases located?
Show the answer
Attached to the epithelial cell membranes of the small intestine. -
Co-transport of amino acids, micelles and chylomicrons
How do glucose and amino acids move from epithelial cells into the blood?
Show the answer
They accumulate inside the cells and then diffuse through the basal membrane into the blood.
Paper 1, Paper 3
Genetic Information, Variation and Relationships Between Organisms
219 questions in the guide, across 18 subtopics. More from this topic
-
Prokaryotic and eukaryotic DNA, chromosomes and histones
Are prokaryotic DNA molecules associated with proteins?
Show the answer
No, prokaryotic DNA is not associated with proteins. -
Features of the genetic code, exons and introns
What proportion of nuclear DNA in eukaryotes codes for polypeptides?
Show the answer
Only a small proportion; much of the nuclear DNA does not code for polypeptides. -
Transcription, RNA polymerase and splicing
How does RNA polymerase separate the two strands of DNA during transcription?
Show the answer
By breaking the hydrogen bonds between base pairs. -
Gene mutations, mutagens and chromosome non-disjunction
What is a base substitution mutation?
Show the answer
A type of gene mutation where one base is replaced by another. -
Meiosis compared with mitosis and random fertilisation
How do mitosis and meiosis differ in their effect on chromosome number?
Show the answer
Mitosis maintains chromosome number, whereas meiosis halves chromosome number.
Paper 2, Paper 3
Energy Transfers in and Between Organisms
195 questions in the guide, across 15 subtopics. More from this topic
-
Photoionisation and ATP from the light-dependent reaction
Define photoionisation in the context of photosynthesis.
Show the answer
Photoionisation is the process by which chlorophyll loses electrons after absorbing light energy. -
Chemiosmosis, photolysis and products for the Calvin cycle
Define photolysis.
Show the answer
Photolysis is the splitting of water molecules using light energy. -
Glasshouse conditions, pigment chromatography and DCPIP
How are the electrons lost from chlorophyll during photoionisation replaced?
Show the answer
Electrons from photolysis of water replace the electrons lost from chlorophyll. -
Glycolysis and its products
What happens to triose phosphate in the third stage of glycolysis?
Show the answer
Triose phosphate is oxidised to pyruvate -
Acetylcoenzyme A and the Krebs cycle
What happens to coenzyme A when acetylcoenzyme A reacts with the four-carbon molecule?
Show the answer
Coenzyme A is released
Paper 2, Paper 3
Organisms Respond to Changes in Their Internal and External Environments
350 questions in the guide, across 28 subtopics. More from this topic
-
IAA, gravitropism and phototropism
How do low and high concentrations of IAA affect cell elongation in roots?
Show the answer
Low concentrations promote cell elongation in roots, while high concentrations inhibit it. -
Rods, cones, colour vision and visual acuity
Define visual acuity.
Show the answer
Visual acuity is the ability to distinguish between two points close together as separate points. -
Depolarisation, action potentials and saltatory conduction
What happens to voltage-gated sodium channels during repolarisation?
Show the answer
They close. -
Transmission at a cholinergic synapse
Describe what happens to acetylcholine after it is released into the synaptic cleft.
Show the answer
It diffuses across the synaptic cleft and binds to specific receptors on the postsynaptic membrane. -
Antagonistic muscle pairs and muscle fibre structure
How does an antagonistic muscle pair produce movement at a joint?
Show the answer
One muscle contracts while the opposing muscle relaxes, pulling the bone in one direction; the roles reverse to produce movement in the opposite direction.
Paper 2, Paper 3
Genetics, Populations, Evolution and Ecosystems
125 questions in the guide, across 11 subtopics. More from this topic
-
Genotype, phenotype and types of allele
What is a dominant allele?
Show the answer
An allele that is expressed in the phenotype when present in either homozygous or heterozygous form. -
Monohybrid and dihybrid crosses, sex linkage and autosomal linkage
In a dihybrid cross between two individuals heterozygous for both genes, what phenotypic ratio is expected assuming complete dominance and independent assortment?
Show the answer
9:3:3:1 -
Epistasis, genetic diagrams and the chi-squared test
What tool is used in a genetic diagram to show all possible combinations of gametes?
Show the answer
A Punnett square. -
Gene pools, allele frequency and Hardy–Weinberg
What condition regarding natural selection must be met for Hardy–Weinberg equilibrium?
Show the answer
There must be no natural selection favouring or disfavouring any genotype. -
Sources of variation and selection pressures
How does crossing over during meiosis contribute to genetic variation?
Show the answer
Crossing over exchanges segments of DNA between homologous chromosomes during prophase I, creating new combinations of alleles on the same chromosome.
Paper 2, Paper 3
The Control of Gene Expression
221 questions in the guide, across 18 subtopics. More from this topic
-
Types of gene mutation and mutagenic agents
Define a substitution mutation.
Show the answer
A type of gene mutation where one base is replaced by a different base -
Totipotent, pluripotent and induced pluripotent stem cells
Define unipotent cells and state where they are found.
Show the answer
Unipotent cells are found in mature mammals and can divide to form only one cell type. -
DNA methylation, histone acetylation and cancer
What are histones?
Show the answer
Proteins that DNA wraps around to form chromatin. -
Benign and malignant tumours, suppressor genes and oncogenes
What structural difference exists between benign and malignant tumours regarding encapsulation?
Show the answer
Benign tumours are usually surrounded by a capsule of fibrous tissue whereas malignant tumours are not encapsulated. -
Genome projects, the proteome and sequencing methods
What range of organisms have had their complete genomes determined through sequencing projects?
Show the answer
A wide range of organisms, including humans.
AQA A-Level Biology Active Recall Guide
The other 1,937 questions, with the answers printed after each section.