A-LEVEL BIOLOGY AQA NOTES
methods of studying cells
Methods of Studying Cells
- There are 3 main types of microscopes used to observe cells:
Light Microscope |
Scanning Electron Microscope |
Transmission Electron Microscope |
|
Medium |
Light Beam |
Electron Beam |
Electron Beam |
Dimensions |
2D |
3D |
2D |
Max Magnification |
X1,500 |
X200,00 |
X2,000,000 |
Max Resolution |
200 nm |
20 nm |
0.1 nm |
- Magnification is how much bigger the image is compared to the original object viewed with the naked eye
- Magnification = (size of image)/(size of object)
- Resolution is how well a microscope distinguishes between two points that are close together.
- Cell fractionation can be used to separate organelles.
- Homogenisation- grinding cells release the organelles into solution
- Filtration- separates organelles & debris
- Ultracentrifugation- using a centrifuge the organelles are separated out in order of mass