Aerobic Respiration

This lesson covers aerobic respiration — the process by which cells release energy from glucose using oxygen — as required by the Edexcel GCSE Combined Science specification (1SC0). You need to recall the word and symbol equations, know where it occurs and understand why organisms need to respire.

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What Is Respiration?

Respiration is a chemical reaction that takes place in every living cell to release energy from glucose. It happens continuously, 24 hours a day, in all living organisms — plants, animals, fungi, bacteria and protists.

Respiration is not the same as breathing:

Term	Meaning
Respiration	A chemical reaction inside cells that releases energy from glucose
Breathing (ventilation)	The mechanical movement of air in and out of the lungs

Exam Tip: Never say "respiration is breathing." Respiration is a cellular process that releases energy. Breathing (ventilation) supplies the oxygen needed for aerobic respiration and removes the CO₂ produced.

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Aerobic Respiration

Aerobic means "with oxygen." Aerobic respiration is the most efficient way for cells to release energy from glucose.

Word Equation

$\text{glucose} + \text{oxygen} \rightarrow \text{carbon dioxide} + \text{water} + \text{energy (ATP)}$glucose+oxygen→carbon dioxide+water+energy (ATP)