Exam-style questions by topic — AQA A-Level Biology
One verified question for each of 53 topics. These are written for this specification and checked by MasteryMind. They are not past-paper questions, and they are not from AQA.
Monomers and polymers
A researcher compares a protein from a bacterium with a protein of the same function from a mammal and finds that both are polymers of amino acids joined by peptide bonds. Why does this finding support the idea that the biochemical basis of life is similar in all living things?
Practise Monomers and polymersCarbohydrates
Starch and glycogen are both polymers of α-glucose, yet glycogen releases glucose more rapidly when it is hydrolysed. Which structural difference best explains this?
Practise CarbohydratesLipids
How does the presence of a carbon-carbon double bond in the R-group affect the shape of a fatty acid chain?
Practise LipidsGeneral properties of proteins
Which pair of chemical groups is found attached to the central carbon of every amino acid?
Practise General properties of proteinsMany proteins are enzymes
What is meant by the activation energy of a reaction?
Practise Many proteins are enzymesStructure of DNA and RNA
In a DNA molecule, which base pairs with adenine?
Practise Structure of DNA and RNADNA replication
Meselson and Stahl grew bacteria in a medium containing heavy nitrogen (¹⁵N) and then transferred them to a medium containing light nitrogen (¹⁴N). After one round of DNA replication, what did they observe in the DNA extracted from the bacteria?
Practise DNA replicationATP
In a cell, an endergonic reaction is coupled to the hydrolysis of ATP. What is the immediate benefit of this coupling?
Practise ATPWater
A plant is exposed to high temperatures. Explain how the properties of water help the plant to survive these conditions.
Practise WaterInorganic ions
Which ion is a component of haemoglobin?
Practise Inorganic ionsStructure of eukaryotic cells
A scientist compares a sperm cell with a palisade cell. Which combination of adaptations correctly matches each cell to its function?
Practise Structure of eukaryotic cellsStructure of prokaryotic cells and of viruses
Which statement best explains why a virus is described as non-living?
Practise Structure of prokaryotic cells and of virusesMethods of studying cells
A student wants to observe the detailed three-dimensional surface topography of a pollen grain. Which microscope would be most suitable?
Practise Methods of studying cellsAll cells arise from other cells
A virus infects a host cell. Which process produces new virus particles?
Practise All cells arise from other cellsTransport across cell membranes
A cell that carries out a high rate of facilitated diffusion of glucose would be expected to have which feature in its membrane?
Practise Transport across cell membranesCell recognition and the immune system
Some pathogens show antigen variability. What effect does this have on the body's ability to respond to a later infection by the same pathogen?
Practise Cell recognition and the immune systemSurface area to volume ratio
Why does a small mammal such as a shrew need to eat far more food per gram of body mass than an elephant does?
Practise Surface area to volume ratioGas exchange
Explain how the contraction of the external intercostal muscles and the diaphragm leads to air entering the lungs.
Practise Gas exchangeDigestion and absorption
Glucose is absorbed from the ileum into the epithelial cells by co-transport. Which ion is co-transported with glucose in this process?
Practise Digestion and absorptionMass transport in animals
Which change in the blood increases the unloading of oxygen from haemoglobin in respiring tissues?
Practise Mass transport in animalsMass transport in plants
According to the mass flow hypothesis, what is the main driving force that moves sugars through the phloem?
Practise Mass transport in plantsDNA, genes and chromosomes
Which statement best describes the nuclear DNA of a eukaryotic cell?
Practise DNA, genes and chromosomesDNA and protein synthesis
Which statement correctly compares the base composition of mRNA and tRNA?
Practise DNA and protein synthesisGenetic diversity can arise as a result of mutation or during
Which of the following best describes how a spontaneous gene mutation can arise during the cell cycle?
Practise Genetic diversity can arise as a result of mutation or duringGenetic diversity and adaptation
A population of beetles lives on two islands. On island A the beetles are eaten by birds that hunt by sight; on island B there are no sight-hunting birds. After many generations, the mean body colour of island A beetles is closer to the colour of the island A background than the mean body colour of island B beetles. Which explanation best accounts for this difference?
Practise Genetic diversity and adaptationSpecies and taxonomy
What is the primary role of courtship behaviour in ensuring reproductive success?
Practise Species and taxonomyBiodiversity within a community
A student compares the biodiversity of a garden pond with the biodiversity of the whole of Britain. Which statement about the habitats involved is correct?
Practise Biodiversity within a communityInvestigating diversity
A random sample of 10 leaves from one tree has a mean length of 6.4 cm. A random sample of 10 leaves from a second tree of the same species has a mean length of 7.1 cm. What is the most appropriate next step when interpreting these two mean values?
Practise Investigating diversityPhotosynthesis (A-level only)
A farmer grows tomatoes in a glasshouse maintained at 25 °C with optimal soil moisture. During winter, the farmer uses artificial lighting to increase the light intensity, but the rate of photosynthesis remains low. Which agricultural practice would be most effective at increasing the rate of photosynthesis under these conditions?
Practise Photosynthesis (A-level only)Respiration (A-level only)
In an investigation into the effect of substrate concentration on the rate of respiration of a yeast culture, the volume of carbon dioxide produced is measured at five substrate concentrations. Explain why a control containing the yeast culture without added substrate is needed, and state one measurement, other than the volume of carbon dioxide, that should be made to calculate the rate.
Practise Respiration (A-level only)Energy and ecosystems (A-level only)
Which group of organisms obtains energy directly from the net primary production of plants?
Practise Energy and ecosystems (A-level only)Nutrient cycles (A-level only)
Saprobiotic microorganisms are important in the phosphorus cycle. Which statement describes their role?
Practise Nutrient cycles (A-level only)Survival and response (A-level only)
Which term describes a directional response in which a mobile organism moves towards or away from a stimulus?
Practise Survival and response (A-level only)Receptors (A-level only)
Explain how the structure of a Pacinian corpuscle allows it to respond specifically to mechanical pressure and produce a generator potential.
Practise Receptors (A-level only)Control of heart rate (A-level only)
A drug blocks the movement of the wave of electrical activity through the atrioventricular node. Which effect on the heart would be expected?
Practise Control of heart rate (A-level only)Nerve impulses (A-level only)
At the resting potential, the sodium-potassium pump moves ions across the axon membrane. Which movement does it produce?
Practise Nerve impulses (A-level only)Synaptic transmission (A-level only)
Which event occurs first when a nerve impulse arrives at the presynaptic membrane of a cholinergic synapse?
Practise Synaptic transmission (A-level only)Skeletal muscles are stimulated to contract by nerves and act as
The biceps and triceps of the upper arm act as an antagonistic pair. Which description explains why both muscles cannot be fully contracted at the same time?
Practise Skeletal muscles are stimulated to contract by nerves and act asPrinciples of homeostasis and negative feedback (A-level only)
During an action potential, the opening of voltage-gated sodium ion channels causes sodium ions to diffuse into the axon. This depolarises the membrane, which causes more voltage-gated sodium ion channels to open. Which statement correctly interprets this mechanism?
Practise Principles of homeostasis and negative feedback (A-level only)Control of blood glucose concentration (A-level only)
What is glycogenesis? Select the correct answer.
Practise Control of blood glucose concentration (A-level only)Control of blood water potential (A-level only)
In which part of the nephron is glomerular filtrate formed?
Practise Control of blood water potential (A-level only)Inheritance (A-level only)
In a chi-squared test comparing observed and expected phenotypic ratios, the calculated chi-squared value is 7.82. The critical value at the 0.05 probability level is 5.99. What is the correct conclusion?
Practise Inheritance (A-level only)Populations (A-level only)
In a population, the frequency of the recessive allele is 0.3. Assuming Hardy–Weinberg equilibrium, what is the frequency of heterozygous individuals?
Practise Populations (A-level only)Evolution may lead to speciation (A-level only)
What term describes the differences in phenotype shown by individuals within a single population of a species?
Practise Evolution may lead to speciation (A-level only)Populations in ecosystems (A-level only)
What name is given to the maximum population size of a species that an ecosystem can support?
Practise Populations in ecosystems (A-level only)Alteration of the sequence of bases in DNA can alter the
A culture of bacteria is exposed to a chemical mutagen. Which prediction about the treated culture is most consistent with the statement that mutagenic agents increase the mutation rate?
Practise Alteration of the sequence of bases in DNA can alter theMost of a cell’s DNA is not translated (A-level only)
During early mammalian development, which type of stem cell can divide and differentiate into any type of body cell, as well as extra-embryonic cells?
Practise Most of a cell’s DNA is not translated (A-level only)Regulation of transcription and translation (A-level only)
A transcriptional factor moves from the cytoplasm into the nucleus of a eukaryotic cell. Which statement describes how this factor can affect a target gene?
Practise Regulation of transcription and translation (A-level only)Gene expression and cancer (A-level only)
Which type of gene normally codes for proteins that slow the cell cycle and so help to prevent the formation of tumours?
Practise Gene expression and cancer (A-level only)Using genome projects (A-level only)
Which feature of the genome of a complex organism means that the proteome cannot easily be predicted from the genome sequence?
Practise Using genome projects (A-level only)Recombinant DNA technology (A-level only)
Which enzyme is used in the polymerase chain reaction to build new DNA strands?
Practise Recombinant DNA technology (A-level only)Differences in DNA between individuals of the same species can be exploited
A screening programme for a rare inherited condition has a detection rate of 99% and a false positive rate of 5%. In a population of 100 000 people, 200 have the condition. Which conclusion about a person who tests positive is best supported by these figures?
Practise Differences in DNA between individuals of the same species can be exploitedGenetic fingerprinting (A-level only)
A patient has a disease-associated allele detected by genetic fingerprinting. The allele codes for a receptor that binds a particular medicine less strongly than the common allele. Which statement best explains how this information can be used in medical diagnosis and treatment?
Practise Genetic fingerprinting (A-level only)
Practise all 1,083 verified questions and see your weak topics.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge