GCSE Required Practical – Biology 1 – Using a light microscope
What’s the point of the practical?
To find out what cells look like and see how big they are and see how they work.
Example Apparatus
- Use a stain to make things
visble (cell wall, nucleus).
- Get the specimen as flat and
thin as possible.
- Start on the smallest lens,
focus, then move up a lens.
- a ruler, or eyepiece scale can
be used to measure size
Magnification = ___image size____
actual object size
What may they ask us about?
- Make sure you can use and rearrange the equation
- Make sure you know the units:
1mm = 1000um
1um = 1000nm
- You may need a ruler to measure the size of images and work out their real size.
- Explain why we can see the nucleus and cell wall but not the mitochondria (they’re far too small and not stained)
- How can we see smaller parts of cells? (An electron microscope has much more resolution and magnification)