Notes

microscope: used to analyse and view cell components and organelles
magnification: how many times bigger the image is produced by the microscope in comparison to the actual size
resolution: the ability to distinguish two objects together as different entities
types of microscopes: optical, electron laser scanning
1. optical microscopes- require light to function which limits the resolution as light does not allow you to see to object closer together by less than half a wavelength which is around 500 to 650 nm ( optical microscopes have a resolution of 200nm) so they can only see organelles such as the nuclei, chloroplasts and mitochondria but cannot see smaller organisms such as the ribosomes, the endoplasmic reticulum and lysosomes. ( max useful magnification is around x1500)
2. electron microscopes- use a beam of electrons that has a smaller wavelength than the optical microscope so can resolve objects close to each other.( resolution of 0.2nm) so it can observe smaller organelles such as ribosomes, endoplasmic reticulum and lysosome. ( magnification of x1500000)
* transmission-a beam of electrons passed through the specimen, denser parts absorb more electrons making it darker on the final part
adv; high resolution so internal structures and organelles are seen in more detail
dis; only used on thin specimens or thin sections of the object viewed, cannot observe living objects as it contains a vacuum so all the water has to be removed, lengthy treatment required to prepare means artefacts can be introduced, colour image is not produced