Sample: Microscopy

 

MICROSCOPY


Exam questions on this section commonly require you to:

  • Compare and contrast how the 2 microscopes work
  • Comment on the limitations of the 2 microscopes
  • Distinguish between the appearance of cells under the light microscope and electron microscope
  • Describe an experiment in which you used light microscopy to view cells – both stained and unstained.

There are two types of microscope used to view cells:

  1. Light Microscope
  2. Electron Microscope

LIGHT MICROSCOPE


  • Uses a beam of light to view specimen
  • Uses glass lenses for magnification
  • Average light microscope magnification – 400 times
  • Eyepiece lens – magnifies image
  • Coarse adjustment wheel – allows for rough focusing
  • Objective lens – Magnifies Image
  • Nosepiece – Revolves different objective lenses
  • Stage/clip – revolves around different objective lenses
  • Mirror/ light source – Supply light
  • Diaphragm/ iris – Allows light intensities to illuminate the image

 

Typical Animal Cell Under Light Microscope

Animal Cell

 

 

 

Typical Plant Cell Under Light Microscope

ELECTRON MICROSCOPE


  • Uses beam of electrons to view specimen
  • Uses magnets for magnification
  • Cannot view living specimens – due to the staining and embedding of magnets
  • Very high magnification- greater than 500,000 times

 

Animal Cell Under Electron Microscope

 

 

 

Plant Cell under Electron Microscope