Life Processes Practice
Solve chapter-level practice questions for Life Processes with reveal-only solutions and quick revision support.
Practice Set 1 — Nutrition and Photosynthesis
Autotrophic vs heterotrophic nutrition, photosynthesis, and human digestion.
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Practice Set 2 — Respiration, Transport, Excretion
Aerobic and anaerobic respiration, double circulation, and the nephron.
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Quick Q&A Before You Revise
Why is diffusion insufficient to meet the oxygen requirement of large multicellular organisms like humans?
In large organisms most cells are deep inside the body and not in contact with the environment. Diffusion is far too slow over long distances, so specialised respiratory and circulatory systems are needed to deliver oxygen quickly to every cell.
What is the advantage of terrestrial organisms over aquatic organisms with respect to obtaining oxygen for respiration?
Air has a much higher concentration of oxygen (about 21%) than the dissolved oxygen in water. So terrestrial organisms have to do less work to obtain the same amount of oxygen and can have higher rates of metabolism.
Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?
Because the amount of dissolved oxygen available in water is low, aquatic animals such as fish must pass large volumes of water over their gills to extract enough oxygen.
How are fats digested in our bodies? Where does this process take place?
In the small intestine. Bile from the liver breaks large fat droplets into smaller ones (emulsification), and then the enzyme lipase from the pancreas and intestine breaks the emulsified fat into fatty acids and glycerol.