# Cold-blooded animals, such as lizards, rely on their surroundings to warm their bodies. A lizard basking in the sun has a higher body temperature than one resting in the shade. Explain why the lizard basking in the sun is able to digest its food more quickly, using ideas about the Maxwell-Boltzmann distribution and activation energy.

> Edexcel A-Level Chemistry (9CH0) — 9.1 Rates and the Maxwell-Boltzmann distribution · Explain · 5 marks

> Cold-blooded animals cannot generate their own body heat. The rate at which they digest food depends on the rate of enzyme-controlled chemical reactions inside their bodies.

## Mark scheme (5 marks)

1. At higher temperature, particles (molecules) have more kinetic energy / move faster
2. The Maxwell-Boltzmann distribution shifts to the right / peak moves to higher energy at higher temperature
3. A greater proportion / more particles have energy equal to or greater than the activation energy
4. There are more successful / effective collisions per unit time
5. Therefore the rate of the digestion reactions is greater / food is broken down more quickly

## Key terms

- [Maxwell-Boltzmann distribution](https://www.gradenine.co.uk/glossary/maxwell-boltzmann-distribution)
- [activation energy](https://www.gradenine.co.uk/glossary/activation-energy)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/cold-blooded-animals-such-as-lizards-rely-7b272835) · Published by Druglandscape Ltd.