F211 - Module 1 Cells

Cell Structure
1. Microscopy
  1. MAGNIFICATION = how large the image is compared to reality
  2. RESOLUTION = the ability to distinguish between two objects or pieces of information in the image
  3. Light Microscope
    1. Magnification - max. x1500
    2. shines light through specimen, and is focused through the objective lens, to produce an image
  4. actual size=image size/magnification
  5. Electron Microscope
    1. Transmission Electron Microscope TEM
      1. use magnets to hit specimen with beam of electrons
      2. 2D Greyscale micrograph is produced
        denser areas are darker bc electron dense = contrast
      3. Magnification - max. x500 000
    2. Scanning Electron Microscope SEM
      1. An electron beam is directed at the sample at an angle
      2. produce a 3D micrograph
        the bounces are recorded to give surface of sample
      3. Magnification - max. x100 000
    3. Advantages
      1. resolution is much higher than light microscope
        can be used to produce detailed images
      2. SEM produces 3D image
    4. Disadvantages
      1. Very expensive
      2. preparation of specimen requires a lot of skills, high level of training
      3. required to be done in a vacuum bc electron beams are deflected by molecules in the air
        Very expensive
  6. staining allows the specimen to be seen. the colour stain may bind to specific cell structures or chemicals on or in the specimen
2. Organelles
  1. mitochondria
    1. 2 membranes, inner membrane heavily folded = cristae, centre = matrix
    2. Role: produces most ATP during respiration, almost all active processes use energy from mitchondria
  2. Nucleus
3. Prokaryotes and Eukaryotes

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F211 - Module 1 Cells

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	Created by Gurdev Manchanda over 9 years ago