Microscopy

• Pathway of light through a microscope:

  Light source ➔ stage ➔ microscope slide ➔ object ➔ objective lens ➔ body tube ➔ eyepiece lens ➔ eye
• Microscopy practical:

  1. Put a thin sample of tissue (e.g. onion epidermis) onto a microscope slide.
  2. Add a few drops of a suitable stain/dye (e.g. iodine).
  3. Place a coverslip on top of the tissue and place the slide onto the microscope stage.
  4. Use the objective lens with the lowest magnification, and focus on the sample.
  5. ncrease the magnification and refocus to see different features of the cell.
• Reasons why we stain tissue when looking through a microscope:

  • Differensiate between living and dead cells.
  • Highlight metabolic processes.
  • Highlight different cellular structures.