LAB 1

• In ancient Greek, 'mikro' means 'of minute size', and 'skopion' refers to 'means of viewing'
• Microscope can be classified based on:

  • Source of light (light, electron, etc.)
  • Arrangement
  • Number of lenses (simple, compound)
  • Method of interaction between the sample, and lens (probe, laser, etc.)
• Simple Microscopes:

  • Uses the power of a single lens to magnify a given sample
• Compound Microscopes:

  • Uses an objective lens to collect an image enhanced by a secondary system of lenses
• Compound Microscopes:

  • Uses multiple lenses to magnify the image of a sample
  • Total magnification is derived by multiplying the ocular lens magnification by the objective lens magnification
• Bright-field Microscopes:

  • Also known as 'Compound Light Microscope'
  • Creates a dark image against a bright background by using light rays
  • Best suited for viewing stained or naturally pigmented specimens
• Dark-field Microscopes:

  • Perfect for illuminating unstained samples against a dark background
  • Uses a special condenser to scatter light and reflect off the material at an angle
• Phase Contrast Microscopes:

  • Enhances the contrast of images of transparent and colorless specimens
  • Enables visualization of cells and cell components that would be difficult to see using an ordinary light microscope
• Differential Interference Contrast Microscopes (DIFC):

  • Known as 'Nomarski microscopy or imaging'
  • Takes advantage of differences in light refraction by different parts of living cells and transparent specimens
• Fluorescence Microscope:

  • Merges magnifying properties of a light microscope with the fluorescence emitting properties of molecules
  • Uses high-intensity light source to trigger fluorescent molecules in the sample
• Confocal Microscope:

  • Known as Confocal Laser Scanning Microscopy (CLSM) or Laser Confocal Scanning Microscopy
  • Uses lasers and fluorescence to create a 3-dimensional image of a sample
• Electron Microscope:

  • Uses a beam of accelerated electrons as a source of illumination
  • Higher resolving power than light microscopes
• Scanning Probe Microscope:

  • Used to create images of nanoscale surfaces and structures or manipulate atoms
  • Involves a physical probe that scans over the surface of a specimen gathering data
• Cryo-electron Microscope:

  • Modification of transmission electron microscopes
  • Enables high resolution of biomolecules by freezing them
• Acoustic Microscope:

  • Studies samples using sound waves for non-invasive sample imaging
• Digital Microscope:

  • Uses a digital camera and a computer for live imaging
  • Some devices have eyepieces, while others are entirely computer controlled
• Proper care and maintenance of microscopes:

  • Carry the microscope with both hands
  • Maintain cleanliness of lenses
  • Proper storage of the microscope
• The resolution of the light microscope is sufficient to produce excellent images of many important cell structures and organelles
• Many diseases have been discovered at the microscopic level, aiding in the discovery of causes and remedies
• Prokaryotic Cells:

  • Simple and most ancient type of cells