Methods of Studying Cells

• Magnification: The number of times bigger the image/drawing is compared to the object/real size.
• Resolution: The minimum distance needed to differentiate between 2 adjacent objects.
• Micrometer: 1 x 10-6m
• Nanometer: 1 x 10-9m
• The material that is put under a microcsope is referred to as the object.
• The apperance of the material when viewed under the microscope is called the image.
• Magnification = size of image ÷ size of real object
• The reolution can also be called resolving power.
• The resolving power depends on the wavelength or form of radiation used in the microscope.
• Increasing the magnification increases the size of the image, but dosen't always increase the resolution.
• Cell Fractionation: The process where cells are borken up and the different organelles they contain are separated out.
• Homogenation: The first stage of cell fractionation when cells are broken up by a homogeniser (blender) and organelles are released from the cell.
• Ultracentrifugation: The second stage of cell fractionation when the fragments in filtered homogenate are separated in a centrifuge.
• Before cell fractionation can begin cells must be placed in a cold, buffered solution of the same water potential as the tissue.
• Cells before cell fractionation are placed in a cold solution to reduce enzyme activity that might break down organelles.
• Cells before cell fractionation are placed into a buffered solution so that the pH dosen't fluctuate. Changes in pH could alter the structure of organelles or affect the functioning of enzymes.
• Cells before cell fractionation are placed into a solution with the same water potental as the tisssue to prevent cells from bursting ot shrinking as a result of osmotic gain or loss of water.
• After homogenation cells are filtered to remove any large pieces of debris. They then go into the centrifuge.
• A centrifuge is first spun slow and the heaviest organelles are forced to the bottom where they form a thin sediment. Then the speed is increased and the next heaviest organelle will form the same process.