Chapter 3 - Cell Structure

Cell Fractionation: 

• Cell fractionation is the process where cells are broken up and isolated into groups of their different organelles
• The tissue being used needs to be placed in a cold, buffered solution of the same water potential as the tissue
• It needs to be cold to reduce enzyme activity, of the same water potential to prevent organelles from bursting or shrinking, and buffered so the pH doesn't fluctuate
• Cells are homogenised to release the organelles from the cell, creating a fluid called a homogenate that is then filtered to femove large debris and complete cells
• The homogenate is then filtered further in a centrifuge in the process of ultracentrifugation - this spins tubes of homogenate at high speeds to get the heaviest organelle to form a pellet at the bottom of the tube
• The heaviest organelle in an animal cell is the nuclei, followed by the mitochondria

The Electron Microscope 

• Uses a beam of electrons…