DEFINITION: The process of enlarging an object in appearance. Image size(mm)= how big the object appears to be (in a picture/ drawing). Actual size (μm)= how big the object is in reality
CALCULATING MAGNIFICATION: Magnification= image size/ actual size
RESOLUTION:
DEFINITION: The ability to distinguish 2 adjacent structures as separate. Higher resolution= higher clarity and detail of the image
CELL FRACTIONATION:
EFFECT: Separates organelles according to size
ORDER OF FRACTIONATION: Nucleus, chloroplasts, mitochondria, lysosomes, endoplasmic reticulum, ribosomes
Cell fractionation
0. Tissue kept in specific conditions before fractionation
The tissue is kept in specific conditions before fractionation: Ice cold (reduces enzyme activity that might damage the cells), isotonic solution (prevents osmosis that could shrink/burst organelles NOT CELLS!), buffered solution (keeps pH constant. Avoids damaging protein structures)
LIGHT MICROSCOPES:
OPTICAL (LIGHT) MICROSCOPES: Visible light passes and is bent through the lens to enable the user to see the specimen. The specimen can be alive and individual cells are generally transparent & their components not distinguishable (unless coloured with special stains) as light has a relatively long wavelength
EFFECTS: Maximum resolution: 0.2 μm. The nucleus and mitochondria can be seen. Maximum magnification: x 1500
Electron microscopes
Use a beam of electrons instead of a beam of light, allowing higher magnification and higher resolving power (more detail can be seen) as electron wavelengths are shorter