# Explain why the resolution of an electron microscope is greater than that of a light microscope.

> OCR A-Level Biology A (H420) — 2.1 Cell structure · Explain · 4 marks

> Biologists use different types of microscopes to study cell ultrastructure. Transmission electron microscopes (TEMs) can resolve structures that are just a few nanometres apart, whereas the best light microscopes cannot resolve structures closer than approximately 200 nm.

## Mark scheme (4 marks)

1. Resolution is limited by the wavelength of the radiation used
2. Electrons have a much shorter wavelength than light
3. A shorter wavelength means two points closer together can still be distinguished as separate
4. Therefore the electron microscope can resolve / distinguish ultrastructure that the light microscope cannot

## Key terms

- [resolution](https://www.gradenine.co.uk/glossary/resolution)
- [electron microscope](https://www.gradenine.co.uk/glossary/electron-microscope)

## Related

- [Revision notes for OCR A-Level Biology A (H420)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-the-resolution-of-an-15816af1) · Published by Druglandscape Ltd.