GCSE Biology revision

Microscopy

Cell structure

AQA 4.1.1.1

Your specification

AQA student objectives

Learning pathway

ALL 🎯

Describe the differences in magnification and resolution between light and electron microscopes.

MOST 🎯🎯

Explain how electron microscopy has increased our understanding of sub-cellular structures and calculate magnification, image size or real size.

SOME 🎯🎯🎯

Apply microscopy data, standard form and magnification calculations to interpret unfamiliar images and determine the scale of cellular structures.

Revision summary

Read on screen, then print for Cornell-style active revision.

Light microscopes are small, relatively cheap, and easy to use, making them ideal for classroom settings
They use light to produce images, which limits their resolution to 02 micrometres (µm)
Any two details closer than 02 µm apart will appear blurry, meaning finer subcellular structures cannot be seen clearly
Light microscopes are suitable for viewing whole cells, such as onion cells, but cannot resolve subcellular structures like mitochondria

1. Light Microscopes: The Classroom ClassicAQA

Light microscopes are small, relatively cheap, and easy to use, making them ideal for classroom settings
They use light to produce images, which limits their resolution to 02 micrometres (µm)
Any two details closer than 02 µm apart will appear blurry, meaning finer subcellular structures cannot be seen clearly
Light microscopes are suitable for viewing whole cells, such as onion cells, but cannot resolve subcellular structures like mitochondria

Electron microscopes use electrons instead of light, giving them a maximum resolution of 01 nanometres (nm)
They are very large, extremely expensive, and difficult to operate, so they are only used by scientists in specialist laboratories
Because a smaller resolution value means finer detail can be distinguished, electron microscopes offer 2,000 times better resolution than light microscopes
Their superior resolution allows much higher magnifications without images becoming blurry

2. Electron Microscopes: High-Tech PowerhousesAQA

Electron microscopes use electrons instead of light, giving them a maximum resolution of 01 nanometres (nm)
They are very large, extremely expensive, and difficult to operate, so they are only used by scientists in specialist laboratories
Because a smaller resolution value means finer detail can be distinguished, electron microscopes offer 2,000 times better resolution than light microscopes
Their superior resolution allows much higher magnifications without images becoming blurry

Electron microscopes can be used to study subcellular structures such as mitochondria, which are too small to be seen clearly with a light microscope
Images taken with electron microscopes can clearly show structures like the nucleus and mitochondria within cells
This level of detail has greatly advanced our understanding of cell biology and the functions of organelles

3. What Can Electron Microscopes Reveal?AQA

Electron microscopes can be used to study subcellular structures such as mitochondria, which are too small to be seen clearly with a light microscope
Images taken with electron microscopes can clearly show structures like the nucleus and mitochondria within cells
This level of detail has greatly advanced our understanding of cell biology and the functions of organelles

Light microscopes have the advantages of being portable, affordable, and simple to use, but are limited by their lower resolution of 02 µm
Electron microscopes provide far greater resolution (01 nm) and magnification, but are costly, large, and require specialist training to operate
When comparing microscopes in an exam, focus on resolution, cost, size, ease of use, and the types of structures each can reveal

4. Comparing the Two: Key Pros and ConsAQA

Light microscopes have the advantages of being portable, affordable, and simple to use, but are limited by their lower resolution of 02 µm
Electron microscopes provide far greater resolution (01 nm) and magnification, but are costly, large, and require specialist training to operate
When comparing microscopes in an exam, focus on resolution, cost, size, ease of use, and the types of structures each can reveal