1. Types
   1. Light Microscope (Compound Microscopes) (resolution <0.2um)
      1. Bright Field
         1. Ordinary Microscope
         2. Dark Image against Brighter Background
         3. Unpigmented cells are not clearly visible (should Kill and Stain the cells)
      2. Dark Field
         1. Bright Image against Darker Background
      3. Phase Contrast
         1. Enhances contrasts of transparent and colorless objects by influencing the optical Path of light
         2. Light passing through transparent part of specimen travels slower so it shifts the comparison to uninfluenced light
         3. The differences captured by Phase-Plate in microscope lead to differences in brightness- Transparent object shines
         4. Applications
            1. Microbial motility
            2. determining shape of living cells
            3. Detecting bacteria components
      4. Fluorescence
         1. Other Microscopes: Produce Image from light that passes through a specimen, Fluorescence: Image itself emits light
         2. Specimen exposed to UV, Violet or Blue light
   2. Electron Microscope (Much grater resolution)
      1. Transmission (analysis internal structure)
         1. works like slide projector
         2. Light transmits through slide, passes through as affected by structure and objects on slides (different intensity passes through)
         3. Spicemen scatters or allow electrons to pass through depending on density of specimen
         4. Denser region - scatter more electrons - appear darker in image as fewer electrons strike that area on screen
         5. Image enlarge on a viewing screen
         6. Only extremely thin slices (20-100 nm) specimen can be viewed to allow absorption of electrons
         7. Sample preparation
            1. Specimen mounted on support
            2. Fixation to stabilize cell structure
            3. Dehydration with organic solvents (acetone or ethanol)
            4. Soak in unpolymerized liquid epoxy plastic - harden into solid block
            5. use ultramicrotome to cut into thin slices
      2. Scanning (analysis surface structure)
         1. Electron beam hits on surface of specimen and discharge tiny shower of secondary electrons captured by special detector-image
         2. Number of secondary electrons reaching detector depends on the nature of specimen's surface
         3. raised area - more secondary electrons enter - appear lighter on screen
         4. Sample preparation
            1. Highly similar to TEM samples except sectioning
            2. Fixed, dehydrated, mounting and coating
2. New Techniques
   1. Confocal Microscope
      1. Uses laser beam
      2. Specimen is flourescently stained
      3. Provides reconstruction of Images
      4. Controllable depth of field
      5. Thick specimens can be analysed
   2. Scanning prob Microscopy
      1. Uses electron
      2. Applies small voltage to the specimen
      3. Allows to view at levels of atoms
   3. Atomic force Microscopy
      1. Forcing electrons on surface at a short distance
      2. no use of voltage
      3. Can be used for surfaces that do not conduct electricity well
3. Magnification Power
   1. Formula
      1. (Eyepiece Magnification Power) x (objective magnification power
4. Parts
   1. Base
      1. Placed on flat surface
   2. Arm
   3. Light source
      1. Controls the intensity of light (an electric illuminator)
   4. Coarse adjustment knob
      1. To focus in low and scanning power
   5. Fine adjustment knob
      1. To focus in high power
   6. stage
      1. To place the slides
   7. Stage clips
      1. To hold the slides
   8. Substage condenser (Diaphragm)
      1. To control the amount of light passing through the specimen and to focus light on it
   9. Ocular (Eyepiece)
      1. to look through , may be single or double (binocular microscopes)
   10. Nosepiece
       1. Holds and revolves the objective lenses
   11. Objectives
       1. normaly 3-4 objective lenses adjust from low to high power
   12. Body tube
       1. Connects eyepiece to objective lenses