# Aerobic respiration is affected by temperature because it is catalysed by enzymes. Explain how a rise in temperature from 20 °C to 70 °C affects the rate of aerobic respiration in a yeast cell.

> Cambridge International IGCSE Biology (0610) — 12.2 Aerobic respiration · Explain · 4 marks

## Mark scheme (4 marks)

1. Rate of aerobic respiration increases as temperature rises (up to the optimum)
2. Because higher temperature gives molecules / enzymes and substrates more kinetic energy, increasing the frequency of successful collisions
3. Above the optimum temperature the rate of respiration decreases / stops
4. Because high temperatures denature the enzymes that catalyse respiration, changing the shape of the active site so substrate cannot bind

## Key terms

- [aerobic respiration](https://www.gradenine.co.uk/glossary/aerobic-respiration)
- [enzyme](https://www.gradenine.co.uk/glossary/enzyme)

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Source: [GradeNine](https://www.gradenine.co.uk/q/aerobic-respiration-is-affected-by-temperature-145695cd) · Published by Druglandscape Ltd.