Microbiology Sample Assignment

Microbiology – Answering Question

  • Evolution of Microscope

In 14th century, the concept evolved with the guidance of grinding in Italy by to improve sight and observance for smaller particles. The idea was adopted by Z. Janssen who induced lenses in tube. It was time of 1590. Robert Hooke spent time on his studies related to microscope and added cork as well as ability to float in water in 1667. In 1675 Anton van Leeuwenhoek developed microscope to look in to blood and bacteria. With the time and the enhancements, the simple, compound and electronic microscopes were in Series of evolution years till 1938. Gerd Binnig and Heinrich Rohrer also invented tunneling scanning microscope. In 1986, they won Nobel Prize due to their work on three dimensional image objects observing microscope.  

  • Measuring Metric Units

The Metric unit for bacteria lies between 1 µm to 10 µm.

  • Wavelength, Resolution, and Numerical Aperture

Wavelength is length of right while resolution is complete and clear view of object overlapping. Resolution has better view than wavelength. Numerical aperture has dimensionless number.

  • Light Properties
    1. Reflection: When light falls on object and bounces back, it is called reflection.
    2. Transmission: When lights fall on objects and passes through it.
    3. Absorption: When light taken by an object and it neither passes nor reflects.
    4. Refraction: When light bends a little, it is termed as refraction.
    5. Fluorescence: When light is observed at low wavelength but emitted at high, it is termed as fluorescence.
    6. Luminescence: light emission at low temperature.
    7. Phosphorescence: Emission of light from any substance or object without burning or combustion procedure.
    8. Diffraction: Light when pass through small hole, it shape changes which is considered as diffraction.
  • Compound Microscope

Eyepiece Lens: Top which provides facilitation of view.

Tube: The connective piece which joins eyepiece and objective lens.

Arm: Support between tube and base.

Base: Bottom which provides balance.

Illuminator: Steady light source glanced on place of mirror at 110 Volts.

Stage: The surface on which slides are placed.

Nose Piece or Turret: The place which objective lens are placed and they hold it.

Objective Lens: The magnifiers with different intensity which provide zoom to observation. They are mainly of 4X, 10X, 40X and 100X and above to 1000X.

Rack Stop: It make adjustment to the lenses and provide slides to the eyepiece lens.

Diaphragm or Iris: Rotating disk with different sizes and holes as well as with different intensity. It relates to the power of microscope.

  • Special Adaptions
    1. Bright Field: Concentrates and transmits lights on the specimen directly.
    2. Dark Field: Put light on specimen with an angle rather than directly.
    3. Phase Contrast Microscopy: Condenser with capacity of accentuates with small difference while observing in a refractive index of different structures.
    4. DIC: It utilizes refractive index difference to view and visualize structure.
    5. Fluorescence: UV excites molecules with release light of higher wavelength.
  • Brief Explanation
    1. Principle of Transmission: Reveals internal view of microbial.
    2. Scanning Tunnel: The instrument which images the surface automatically.
    3. Scanning Electron Microscopy: It produces image with the focus beam of electrons.
    4. Difference: The Transmission principle involves the behavior of light while scanning tunnel automatically creates images and scanning electron involve electron focus beam for image.
  • Techniques
    1. Wet Mounts: Use for living organism.
    2. Smears: thin layer on microscope slide.
    3. Staining: when molecule blind to a structure it creates staining.
  • Gram stain
    1. Preparing Slides: Microbial smears are prepared through oil or grease.
    2. Labeling: They are then labeled.
    3. Preparing Smear
      1. Bacterial Suspensions in Broth: Sterile and then placed loopful of broth.
      2. Bacterial Plate Cultures: Place drop of saline solution on slide. Sterilize and cool the loop.
  • Swab Samples: Roll the Swab over cleaned glass slide.
  1. Heat Fixing: Dry Smear, pass flame of Bunsen through two-three times.
  2. Procedure: The Steps of Gram Strain. The experimentation phase.