Core Practical 6

• What is the purpose of microscopy?

  To increase magnification and resolution
• What are the two main types of microscopes?

  Optical and electron microscopes
• What are the two types of electron microscopes?

  Transmission and scanning
• How is magnification calculated?

  By dividing size of image by actual object size
• What equipment is needed for microscopy of a plant stem?

  • Plant stem
  • Acidified phloroglucinol in ethanol
  • Optical microscope
  • Microscope slides and coverslips
  • Scalpel
  • Razor blade
  • Paintbrush
  • White tile
  • Watch glass
  • Pipette
  • Wax crayon
• What are the steps to prepare a plant stem for microscopy?

  1. Calibrate eyepiece graticule with stage micrometer.
  2. Cut thin transverse sections of the plant stem.
  3. Place section on slide, draw lines with wax crayon.
  4. Add concentrated phloroglucinol and cover slip.
  5. Set microscope to lowest magnification and focus.
  6. Observe and draw the stem.
  7. Measure stem diameter and vascular bundle.
• What should be used to draw biological diagrams?

  HB pencil and unlined paper
• How should biological drawings be labeled?

  Labels should be in pencil
• What are the tips for making effective biological drawings?

  • Draw in the center of the page
  • Take up at least half of the paper
  • Use a ruler for straight lines
  • Use clear lines without smudging
  • Only draw what is visible
  • Outline first, no shading or color
  • Write lens power used on the diagram
• What are the hazards and precautions when using acidified phloroglucinol?

  Hazard: Corrosive and highly flammable

  Precautions:

  • Wear eye protection
  • Avoid skin contact
  • Wash off skin immediately
  • Flood eyes/cuts with cold water
• What are the hazards and precautions when using a razor?

  Hazard: Cuts from sharp object

  Precautions:

  • Cut away from fingers
  • Use forceps to hold sample
  • Keep away from edge of desk
  • Elevate cuts and apply pressure
• What are the hazards and precautions when handling broken glass?

  Hazard: Cuts from sharp object

  Precautions:

  • Handle slides and coverslips carefully
  • Keep glassware away from desk edge
  • Elevate cuts and apply pressure
  • Do not remove glass from wound
• What are the hazards and precautions when using ethanol?

  Hazard: Irritant and flammable

  Precautions:

  • Wear eye protection
  • Keep away from flames
  • Keep away from desk edge
  • Wash eyes and skin with cold water