Biology Topic Practice

GCSE Biology Anaerobic Respiration

When oxygen is in short supply, cells can respire anaerobically. This process releases less energy than aerobic respiration.

These questions look simple — but cost marks.

What is Anaerobic Respiration?

"Anaerobic respiration is an exothermic reaction that releases energy from glucose without using oxygen, producing lactic acid in animals or ethanol in yeast."

Question 1

What is the main product of anaerobic respiration in human muscles?

Question 2

What are the products of anaerobic respiration in yeast?

Question 3

Why does anaerobic respiration transfer less energy than aerobic respiration?

Oxygen Debt & Fermentation

In muscles, anaerobic respiration produces lactic acid, leading to an oxygen debt.

In yeast, it produces ethanol and carbon dioxide, a process called fermentation.

Exam Tip

Remember that anaerobic respiration in yeast is economically important for making bread and alcoholic drinks.

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