Exam-style questions by topic — OCR A-Level Biology
One verified question for each of 32 topics. These are written for this specification and checked by MasteryMind. They are not past-paper questions, and they are not from OCR.
Planning
A student investigates the effect of light intensity on the rate of photosynthesis in pondweed. Which variable must be controlled so that the comparison is fair?
Practise PlanningImplementing
A student wants to observe onion cells under a light microscope. Which technique correctly prepares a temporary slide?
Practise ImplementingAnalysis
A student calculates a magnification as 0.000625 and must express it to two significant figures. Which value is correct?
Practise AnalysisEvaluation
A student records four temperatures of 21.0 °C, 21.2 °C, 20.9 °C and 21.1 °C, then a fifth of 34.5 °C. Which statement best explains why the fifth reading should be treated as an anomaly?
Practise EvaluationPractical skills - Research and referencing
A student writes a report and includes a journal article in the reference list. Which detail is needed so a reader can locate that specific article?
Practise Practical skills - Research and referencingPractical skills - Use and application of scientific methods and practices
A student calculates a mean from five repeat readings and wants to show the variability of the data alongside the mean. Which presentation is most appropriate?
Practise Practical skills - Use and application of scientific methods and practicesUse of apparatus and techniques
A student needs 10 cm³ of a 0.50 mol dm⁻³ solution made from a 2.0 mol dm⁻³ stock. What volume of stock must be diluted to 10 cm³?
Practise Use of apparatus and techniquesCell structure
A micrograph shows a cell with a rigid outer layer, a large central vacuole and many oval organelles with internal folds. Which cell type is this most likely to be?
Practise Cell structureBiological molecules
Which of the following is a use of chromatography in biology?
Practise Biological moleculesNucleotides and nucleic acids
Which three components make up a single nucleotide?
Practise Nucleotides and nucleic acidsEnzymes
In the lock-and-key model of enzyme action, what does the active site represent?
Practise EnzymesBiological membranes
Which membrane component is a protein with a carbohydrate chain attached, positioned on the outer surface and involved in cell recognition?
Practise Biological membranesCell division, cell diversity and cellular organisation
A single-celled organism reproduces by mitosis every 30 minutes. Starting from one cell, how many cells are present after 2 hours, and why does this show the significance of mitosis in its life cycle?
Practise Cell division, cell diversity and cellular organisationExchange surfaces
A student claims that normal exhalation is driven mainly by contraction of the internal intercostal muscles. Which statement best evaluates this claim?
Practise Exchange surfacesTransport in animals
Why does the oxygen dissociation curve of haemoglobin have a sigmoid (S) shape?
Practise Transport in animalsTransport in plants
In a transverse section of a herbaceous dicotyledonous root, where is the xylem tissue positioned?
Practise Transport in plantsCommunicable diseases, disease prevention and the immune system
A student claims that a particular bacterium infecting humans is spread by direct contact. Which observation would provide the strongest evidence for this claim?
Practise Communicable diseases, disease prevention and the immune systemBiodiversity
A large habitat is split by a new road into two smaller patches. Which explanation best describes why biodiversity may fall over time?
Practise BiodiversityClassification and evolution
A scientist in Japan and a scientist in Brazil both study the same beetle and use the name Lucanus cervus for it. Which advantage of the binomial system does this situation best illustrate?
Practise Classification and evolutionCommunication and homeostasis
Evaluate the statement: 'A single-celled organism does not need a communication system because all its life processes occur within one cell.'
Practise Communication and homeostasisExcretion as an example of homeostatic control
In a patient with severe liver disease, blood albumin concentration falls and fluid accumulates in tissues. Which function of the liver best explains this observation?
Practise Excretion as an example of homeostatic controlNeuronal communication
What is the approximate resting potential of a typical mammalian neurone?
Practise Neuronal communicationHormonal communication
Why does a hormone such as insulin affect liver cells but not, for example, most skin cells?
Practise Hormonal communicationPlant and animal responses
Which neurotransmitter is released by parasympathetic neurones at the sinoatrial node to slow the heart?
Practise Plant and animal responsesPhotosynthesis
A plant is grown in light enriched in wavelengths that chlorophyll a absorbs poorly but that accessory pigments absorb well. Predict the effect on the rate of the light-dependent stage compared with growth in white light of the same intensity.
Practise PhotosynthesisRespiration
In a eukaryotic cell such as a human muscle fibre, which product is formed when pyruvate is reduced in the absence of oxygen?
Practise RespirationCellular control
A mutation in a Hox gene causes a body segment to develop a structure normally found on a different segment. Explain how a single gene mutation can produce this change.
Practise Cellular controlPatterns of inheritance
A cross produces offspring in a ratio of 9:3:4 instead of 9:3:3:1. What does this modified ratio indicate?
Practise Patterns of inheritanceManipulating genomes
A researcher needs to sequence many samples quickly and cheaply. Which feature of next-generation sequencing makes it most suitable?
Practise Manipulating genomesCloning and biotechnology
A manufacturer wants to produce a metabolite that is only made when the microorganisms are growing slowly. Which fermentation approach and condition would best maximise yield of this product?
Practise Cloning and biotechnologyEcosystems
What name is given to the first organisms to colonise an area of bare rock at the start of primary succession?
Practise EcosystemsPopulations and sustainability
A farmer harvests a crop of reeds from a wetland each winter but leaves part of the reed bed uncut. Explain how leaving an uncut area helps the reed harvest remain sustainable.
Practise Populations and sustainability
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