Edexcel A-Level Biology B sample questions and answers (9BI0)
Guide overview All 10 topics Sample questions Papers and weighting Look inside Questions and answers
50 sample questions and answers
Taken from every topic of Edexcel A-Level Biology B, specification 9BI0. The full guide has 2,073.
Paper 1, Paper 2, Paper 3
Biological Molecules
256 questions in the guide, across 19 subtopics. More from this topic
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Monosaccharides, disaccharides and polysaccharides
How does the position of the hydroxyl group on carbon-1 in beta glucose differ from alpha glucose?
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In beta glucose, the hydroxyl group on carbon-1 is positioned above the plane of the ring. -
Starch, glycogen and cellulose structure
How does the helical structure of amylose contribute to its storage function?
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The helical structure makes amylose compact, allowing efficient storage. -
Saturated and unsaturated fats and lipid properties
Why are saturated lipids typically solid at room temperature?
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Their straight fatty acid chains pack closely together, increasing intermolecular forces. -
Primary, secondary, tertiary and quaternary structure
How do ionic bonds form in proteins and what is their role?
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Ionic bonds form between oppositely charged R groups (e.g., between positively and negatively charged side chains) and help stabilise protein structure. -
The structure of DNA
How many hydrogen bonds link guanine to cytosine in DNA?
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Three hydrogen bonds.
Paper 1, Paper 2, Paper 3
Cells, Viruses and Reproduction of Living Things
243 questions in the guide, across 16 subtopics. More from this topic
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Cell theory and eukaryotic cell structure
What is the size of eukaryotic ribosomes and what is their function?
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Eukaryotic ribosomes are 80S in size, larger than prokaryotic ribosomes, and are the site of protein synthesis. -
Microscopy, magnification and resolution
Why must magnification be stated on a biological drawing?
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Magnification must be stated to indicate how much larger the drawing is compared to the actual specimen. -
Virus structure and classification
What type of nucleic acid does tobacco mosaic virus (TMV) contain?
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RNA. -
Treating viral disease and the ethics of untested drugs
What outbreak exemplifies the importance of preventing viral spread through public health measures?
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The 2014 Ebola outbreak in West Africa. -
Mitosis and the behaviour of chromosomes
What stage of mitosis comes after metaphase?
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Anaphase.
Paper 1, Paper 2, Paper 3
Classification and Biodiversity
134 questions in the guide, across 8 subtopics. More from this topic
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The hierarchy of classification
What is the fourth level in the classification hierarchy, positioned between phylum and order?
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Class. -
Defining a species
Why is the biological species concept problematic when classifying extinct organisms known only from fossils?
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It cannot be applied because interbreeding and production of fertile offspring cannot be tested in extinct organisms. -
DNA sequencing and molecular phylogeny
How can gel electrophoresis be used to distinguish between different species?
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By comparing banding patterns of DNA fragments; different species produce different patterns. -
Five kingdoms, three domains and peer review
Which kingdom in the five-kingdom model includes unicellular eukaryotes and algae that do not fit into other eukaryotic kingdoms?
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Protoctista. -
Natural selection, adaptation and drug resistance
Define the term niche in an ecological context.
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The role an organism plays in its ecosystem, including its habitat, resources used, and interactions with other organisms.
Paper 1, Paper 2, Paper 3
Exchange and Transport
383 questions in the guide, across 23 subtopics. More from this topic
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Surface area to volume ratio
State the formula for calculating surface area to volume ratio.
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SA:V ratio = surface area ÷ volume. -
Diffusion, osmosis and facilitated diffusion
State the equation used to calculate water potential.
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ψ = P + π, where ψ is water potential, P is pressure potential and π is solute potential. -
Dissecting the insect gas exchange system
How should the number of organisms used in dissection be managed ethically?
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The number used should be minimised. -
The structure of the heart and blood vessels
What is the tunica intima of an artery?
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The tunica intima is the innermost layer of an artery wall, consisting of endothelium. -
Myogenic stimulation and ECG traces
What is the function of the bundle of His?
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The bundle of His conducts electrical impulses from the AVN down through the septum to the apex of the heart.
Paper 1, Paper 3
Energy for Biological Processes
181 questions in the guide, across 12 subtopics. More from this topic
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An overview of aerobic respiration
Name the first stage of aerobic respiration.
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Glycolysis. -
Glycolysis
What would happen to the products of glycolysis if the cell lacked NAD⁺?
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NADH could not be formed because NAD⁺ is required to accept hydrogen atoms; glycolysis would stall as the oxidation steps could not proceed. -
The electron transport chain
What happens to the energy released as electrons pass along the electron transport chain?
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It is used to pump protons (hydrogen ions) from the mitochondrial matrix into the intermembrane space. -
Chemiosmosis and ATP yield
How does the folded structure of the inner mitochondrial membrane benefit oxidative phosphorylation?
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It increases the surface area available for the electron transport chain and ATP synthase, allowing more ATP to be produced. -
Measuring respiration with a respirometer
How should organisms be handled during respirometer experiments to ensure their safe use?
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Handle organisms carefully to minimise stress and ensure appropriate containment.
Paper 1, Paper 3
Microbiology and Pathogens
191 questions in the guide, across 13 subtopics. More from this topic
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Culturing microorganisms and aseptic technique
At what temperature are microorganisms incubated in school laboratories, and why?
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25°C, to reduce the risk of growing human pathogens, which grow best at temperatures closer to 37°C. -
Measuring bacterial growth
What is the purpose of a calibration curve in turbidity measurements?
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It relates absorbance to cell concentration, allowing turbidity readings to be converted to cell numbers. -
Bacteria as pathogens
Which genus of bacteria is associated with pathogenicity through exotoxin production?
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Staphylococcus species. -
The action of antibiotics
Why do bacteriostatic antibiotics require a functional host immune system to be effective?
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Because they only halt bacterial growth; the host immune system must then eliminate the bacteria. -
Other pathogenic agents
Besides respiratory droplets, how else can influenza virus be transmitted?
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By contact with contaminated surfaces followed by touching the mouth, nose or eyes.
Paper 1, Paper 3
Modern Genetics
100 questions in the guide, across 8 subtopics. More from this topic
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Using gene sequencing
Why is the temperature raised to 72°C during the extension phase of PCR?
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This is the optimum temperature for DNA polymerase (typically Taq polymerase) to synthesise new DNA strands. -
Transcription factors and RNA splicing
How do transcription factors influence the activity of RNA polymerase?
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They influence the recruitment of RNA polymerase to the promoter region, either enhancing or inhibiting its binding. -
Epigenetics and gene expression
In DNA methylation, which DNA base has methyl groups added to it?
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Cytosine bases. -
Stem cells
What is the differentiation potential of pluripotent stem cells?
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They can differentiate into any cell type of the body but not extraembryonic tissues. -
Producing recombinant DNA
Why are sticky ends useful in genetic engineering?
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Sticky ends are complementary single-stranded overhangs that can form hydrogen bonds with other complementary sticky ends, allowing DNA fragments to join together.
Paper 2, Paper 3
Origins of Genetic Variation
103 questions in the guide, across 8 subtopics. More from this topic
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Mutation, meiosis and random fertilisation
State the formula for the number of possible gamete combinations produced by independent assortment, and define the variable.
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The formula is 2ⁿ, where n is the haploid chromosome number. -
Genotype, phenotype and monohybrid inheritance
What does it mean for an allele to be dominant?
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A dominant allele is expressed in the phenotype when present in either homozygous or heterozygous form. -
Dihybrid crosses and pedigree diagrams
How are affected individuals indicated in a pedigree diagram?
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By filled (shaded) symbols. -
Autosomal linkage and sex linkage
In Drosophila, what are the dominant and recessive phenotypes for body colour and wing length?
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Grey body and long wings are dominant; black body and vestigial wings are recessive. -
The chi-squared test in genetics
After squaring the differences in a chi-squared test, what is done with each (O − E)² value?
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Each is divided by the expected value (E) for that category.
Paper 2, Paper 3
Control Systems
265 questions in the guide, across 19 subtopics. More from this topic
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Homeostasis and negative feedback
Define negative feedback.
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A control mechanism where a deviation from the set point triggers a response that returns the system towards the set point. -
Plant growth substances
Explain the role of gibberellin during seed germination in cereals.
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Gibberellin stimulates the production of amylase, which digests starch reserves to provide sugars for the growing embryo. -
Phytochrome and photomorphogenesis
Which pigment controls photomorphogenesis in plants?
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Phytochrome. -
Brain regions and divisions of the peripheral nervous system
Which brain region is responsible for initiating voluntary movement?
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The cerebrum. -
Resting potential and the action potential
Why is the axon membrane more permeable to potassium ions than sodium ions at rest?
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Because potassium leak channels are open at rest, allowing K⁺ to diffuse out of the axon.
Paper 2, Paper 3
Ecosystems
217 questions in the guide, across 12 subtopics. More from this topic
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Ecosystems, habitats and niches
Give an example of a very large ecosystem.
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An ocean or a tropical rainforest. -
Pyramids of numbers, biomass and energy
Why are pyramids of energy always upright?
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Energy is lost at each transfer, so each successive trophic level always has less energy than the one below, providing the most accurate representation of energy flow. -
Choosing the right ecological technique
Why might different sampling methods give different estimates of population size?
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Spatial distribution patterns of organisms can cause variation in estimates depending on the sampling method used. -
Presenting data in tables and graphs
When should data be plotted as a line graph?
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When both variables are continuous and the independent variable has been deliberately changed, such as rate of transpiration against wind speed, with the independent variable on the x-axis. -
Productivity and energy transfer efficiency
Explain how respiration causes energy loss between trophic levels.
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Organisms release energy as heat during metabolic processes; this heat energy cannot be transferred to the next trophic level.
Edexcel A-Level Biology B Active Recall Guide
The other 2,023 questions, with the answers printed after each section.