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EnglandBiology

Topic 8: Exchange and transport in animals

3 dot points across 3 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

Why do larger organisms need exchange surfaces, and how are the alveoli adapted for gas exchange?

Explain the need for exchange surfaces and a transport system using surface area to volume ratio, how the alveoli are adapted for gas exchange, and the factors affecting the rate of diffusion including Fick's law.
A focused answer to Edexcel GCSE Biology 8.1 to 8.5B, covering the need for exchange surfaces and transport, surface area to volume ratio, how the alveoli are adapted for gas exchange, and Fick's law.
10 min answer →

What is cellular respiration, and how do aerobic and anaerobic respiration differ?

Describe cellular respiration as an exothermic reaction that releases energy, compare aerobic and anaerobic respiration, and investigate the rate of respiration in living organisms.
A focused answer to Edexcel GCSE Biology 8.9 to 8.11, covering cellular respiration as an exothermic reaction, the comparison of aerobic and anaerobic respiration in animals and plants, and the respiration-rate core practical.
9 min answer →

How are the blood, blood vessels and heart adapted to transport substances around the body?

Explain how the structures of the blood, the blood vessels and the heart are related to their functions, and calculate cardiac output from stroke volume and heart rate.
A focused answer to Edexcel GCSE Biology 8.6 to 8.8 and 8.12, covering the structure and function of red and white blood cells, plasma and platelets, the blood vessels, the heart and circulation, and cardiac output calculations.
10 min answer →