There are 2 types of microscopes you need to know about for your exams. They are:
- Light Microscope
- Electron Microscope
You would have used a light microscope in the practical looking at the onion cells or your own cheek cells.
But what are the differences between the 2?

A light microscope is used to see individual cells and larger organelles* e.g. the nucleus or mitochondria
An electron microscope is used to see the finer detail and smaller organelles e.g. ribosomes or the detail/structure inside of the mitochondria
*organelles – the parts of the cell, we have organs and the cells have organelles
*resolution – the ability to distinguish 2 points before, making a clearer (sharper) image.