GCSE Biology Daily Practice (Higher)
Mark Scheme — 16 marks total
Higher TierMarking Instructions
- • Accept equivalent answers unless the mark scheme states otherwise.
- • M marks are for method — award even if the final answer is wrong.
- • A marks are for accuracy — only award if the method mark has been earned.
- • B marks are independent and can be awarded without other marks.
- • Where a range of answers is acceptable, this is indicated in the mark scheme.
Describe two ways a sperm cell is adapted for its function.
Acceptable Answer
Streamlined head for swimming through fluid. Many mitochondria in the middle section to provide energy for the tail. Long tail (flagellum) for propulsion. Acrosome at the tip contains enzymes to digest the egg membrane.
A plant is kept in the dark for 48 hours, then placed in bright light with one leaf covered in foil. (a) Why was it kept in the dark first? (b) After 6 hours in light, the leaves are tested for starch. Predict the results.
Acceptable Answer
(a) To destarch the plant — remove all existing starch so a fair test can show where new starch is produced. (b) The uncovered leaf will test positive for starch (turns blue-black with iodine) because it could photosynthesise. The covered leaf will test negative (stays brown/yellow) because no light reached it for photosynthesis.
Explain how the structure of the small intestine is adapted for absorbing digested food molecules.
Acceptable Answer
Villi increase the surface area massively. Each villus is one cell thick (short diffusion distance). Rich blood supply maintains a steep concentration gradient. Lacteals absorb fatty acids and glycerol. The small intestine is very long, providing a huge total surface area.
Describe the differences between aerobic and anaerobic respiration.
Acceptable Answer
Aerobic: uses oxygen, produces CO₂ and water, releases lots of energy, happens in mitochondria. Anaerobic (animals): no oxygen, produces lactic acid, releases much less energy, happens in cytoplasm. Anaerobic (yeast): produces ethanol and CO₂.