Free·GCSE Biology
Free GCSE Biology Questions and Answers
12 questions, one from each topic, with the answer that takes every mark and what it is worth. Nothing to sign up to and nothing to download — they are on this page.
Cell biology and microscopy, Organisation and transport, Infection and response, Bioenergetics, Homeostasis and response, Inheritance, variation and evolution, Ecology, Apparatus and techniques and Working scientifically
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Explain how the shape of a root hair cell helps it to take up water.
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The full-mark answer · 3 marks
The long, narrow extension gives the cell a large surface area in contact with the soil. Water moves in by osmosis, and the rate of osmosis increases with the surface area available, so water is absorbed faster than it would be through a flat surface.
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Explain why an organism the size of a mouse cannot rely on diffusion alone to supply its cells with oxygen.
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The full-mark answer · 4 marks
As size increases, volume increases faster than surface area, so the surface area to volume ratio decreases. The exchange surface is too small, and the diffusion distance to the innermost cells too great, for oxygen to be supplied as quickly as the cells respire. A specialised exchange surface and a transport system are needed instead.
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Name the enzyme that breaks down starch.
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The full-mark answer · 1 mark
Amylase.
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Describe how you would test a food sample for protein.
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The full-mark answer · 2 marks
Add Biuret solution to the sample. It changes from blue to purple if protein is present.
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Name the type of pathogen that causes measles.
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The full-mark answer · 1 mark
A virus.
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Describe two ways in which pathogens are spread between people.
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The full-mark answer · 2 marks
In droplets breathed out when an infected person coughs or sneezes, which are inhaled by someone else; and by direct contact with an infected person or a contaminated surface.
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Write the word equation for photosynthesis.
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The full-mark answer · 2 marks
carbon dioxide + water → glucose + oxygen (light energy required)
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Name the hormone that lowers blood glucose concentration.
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The full-mark answer · 1 mark
Insulin.
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Name the type of cell division that produces gametes.
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The full-mark answer · 1 mark
Meiosis.
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Name three abiotic factors that could affect the size of a plant population.
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The full-mark answer · 3 marks
Light intensity, temperature and the availability of water.
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Describe how you would prepare a slide of onion epidermis cells and view them under a light microscope.
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The full-mark answer · 4 marks
Peel a single thin layer of epidermis from the onion and place it flat on a slide in a drop of water. Add a drop of iodine solution to stain the nuclei. Lower a cover slip with a mounted needle so no air is trapped. Place the slide on the stage, focus first with the lowest power objective using the coarse focus, then switch to a higher power and use the fine focus.
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Explain the difference between an accurate measurement and a precise one.
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The full-mark answer · 3 marks
An accurate measurement is close to the true value. A precise set of measurements is one in which repeats are close to each other. A set can be precise but not accurate, if every reading is wrong by the same amount — and repeating them will not reveal it.
What the book adds
These are the answers that score everything. GCSE Biology Questions & Answers is the other half: the same questions answered weakly, middlingly and strongly, the mark each version scores, what separates them, and the mark scheme behind it — a hundred questions across every topic, written for the teacher marking them rather than the pupil sitting them.