OCR GCSE Combined Science Biology, Higher tier sample questions and answers (J250)
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30 sample questions and answers
Taken from every topic of OCR GCSE Combined Science Biology, Higher tier, specification J250. The full guide has 861.
Paper 7 (Biology)
Cell Level Systems
197 questions in the guide, across 9 subtopics. More from this topic
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Microscopy, and sub-cellular structures
Why does a very active cell such as a muscle cell contain large numbers of mitochondria?
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Mitochondria contain the enzymes for cellular respiration, so more of them supply more energy for the cell's work. -
DNA structure: polymer, double helix and nucleotides
Give one example of a biological polymer other than DNA.
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Starch, or a protein. -
Enzyme action, and investigating enzymes
What does the lock and key hypothesis describe?
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The substrate fits into the active site as a key fits a lock, so only a matching substrate can bind. -
Cellular respiration as an exothermic process
Name three processes in an organism that depend on the ATP supplied by respiration.
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Muscle contraction, active transport and the building of large molecules such as proteins. -
Aerobic and anaerobic respiration compared
Which substrate is broken down in both aerobic and anaerobic respiration?
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Glucose.
Paper 8 (Biology)
Community Level Systems
51 questions in the guide, across 4 subtopics. More from this topic
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Cycling materials, and the role of microorganisms
Explain why materials such as carbon and nitrogen must be recycled in an ecosystem.
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The supply of them is limited, so they have to be returned to the non-living surroundings for other organisms to take up and use again. -
Cycling materials, and the role of microorganisms
How do decomposers return carbon to the air?
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They respire as they break down dead material, releasing carbon dioxide. -
The carbon and water cycles, and decomposition
Describe how the carbon in a dead animal returns to the air.
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Decomposers feed on the remains and release carbon dioxide as they respire. -
The carbon and water cycles, and decomposition
Explain why the water cycle provides land organisms with fresh water.
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Evaporation leaves dissolved salts behind, so the water that condenses and falls as rain is fresh and can be used by organisms on land. -
Levels of organisation, and abiotic and biotic factors
All the oak trees growing in one wood are an example of which level of organisation?
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A population.
Paper 8 (Biology)
Genes, Inheritance and Selection
118 questions in the guide, across 8 subtopics. More from this topic
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Genetic terms, and the genome
What does homozygous mean?
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Carrying two identical alleles of a gene. -
Genome, environment and mutations
Explain why height in humans shows continuous variation.
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It is controlled by several genes acting together, and it is also affected by environmental factors such as diet. -
Haploid, diploid and meiosis
A plant has 14 chromosomes in each of its leaf cells. How many chromosomes are in each of its pollen grain nuclei?
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Seven, because gametes are haploid and carry half the number found in a body cell. -
Single gene inheritance and Punnett squares
Two black-furred animals produce a brown-furred offspring, where the allele B for black is dominant to the allele b for brown. Explain how this is possible.
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Both parents are heterozygous Bb, so each can pass on b and produce a bb offspring. -
Sex determination and characteristics controlled by many genes
A Punnett square is drawn for a cross between an XX mother and an XY father. What four combinations fill the four boxes?
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XX, XX, XY and XY.
Paper 8 (Biology)
Global Challenges
240 questions in the guide, across 13 subtopics. More from this topic
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Field investigations, and human impact on ecosystems
What is a pooter and how does it work?
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A small jar with two tubes for collecting insects; the user sucks on one tube so the insect is drawn through the other into the jar, and gauze stops it being swallowed. -
Maintaining biodiversity, monitoring conservation and ecotourism
What is ecotourism?
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Tourism that lets visitors see wildlife in its natural habitat while limiting damage to that habitat and returning money to local people. -
Health, disease, and types of disease
Explain why someone with a poor diet is more likely to catch an infectious disease.
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A shortage of nutrients weakens the immune system, so fewer white blood cells and antibodies are made to fight the pathogen. -
Interactions between diseases, and how they spread
Explain why a single infected plant can lead to the loss of an entire field of crop.
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The plants are close together and genetically very similar, so the pathogen spreads rapidly and every plant is equally susceptible. -
White blood cells, antibodies and platelets
What is an antibody, and which cell produces it?
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A protein that binds to a specific antigen on a pathogen; it is produced by a lymphocyte.
Paper 7 (Biology)
Organism Level Systems
108 questions in the guide, across 8 subtopics. More from this topic
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The nervous system and coordinated responses
What is an effector?
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A muscle or a gland that carries out the response when an impulse arrives from a motor neurone. -
The reflex arc
Explain why a reflex arc produces a faster response than a voluntary action.
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The impulse passes through only three neurones and two synapses and does not travel to the conscious part of the brain for a decision to be made. -
Hormonal coordination, thyroxine and adrenaline
Where are the adrenal glands found?
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One sits just above each kidney. -
Hormones in reproduction and the menstrual cycle
What is the role of progesterone in the menstrual cycle?
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It maintains the thick lining of the uterus so it is ready for a fertilised egg to implant. -
Contraception and treating infertility
What is sterilisation, and why does it suit only some people?
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The sperm ducts or the oviducts are cut or tied so gametes can never meet; it is meant to be permanent and is very difficult to reverse.
Paper 7 (Biology)
Scaling Up
147 questions in the guide, across 9 subtopics. More from this topic
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Diffusion, osmosis and active transport
What happens to a plant cell placed in a concentrated salt solution?
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Water leaves it by osmosis, so the cell loses its turgor and the membrane pulls away from the cell wall. -
Mitosis, the cell cycle and cell differentiation
Why is mitosis important to an organism that reproduces asexually?
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It produces offspring that are genetically identical to the parent. -
Stem cells in animals and meristems in plants
What are the two things a stem cell can do when it divides?
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It can make more stem cells, or produce cells that go on to differentiate into specialised types. -
Surface area to volume ratio and exchange surfaces
Why can a single-celled organism rely on diffusion across its surface alone?
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Its surface area to volume ratio is very large and no part of it is far from the surface, so diffusion supplies its needs fast enough. -
The circulatory system, the heart and blood vessels
Which vessels carry blood away from the heart and which return it?
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Arteries carry blood away from the heart and veins return blood to it.
OCR GCSE Combined Science Biology, Higher tier Active Recall Guide
The other 831 questions, with the answers printed after each section.