RP2

• Where in plants can cells undergoing mitosis be found?

  Meristem tissue at shoot and root tips.
• What is the mitotic index?

  The ratio of cells undergoing mitosis to the total number of cells in a sample.
• Outline the procedure to prepare a root tip slide.

  1. Warm 1M HCI to 60°C in a water bath.
  2. Cut a root tip using a scalpel and add to the HCI. Leave for 5 minutes.
  3. Remove from HI and wash with distilled water.
  4. Cut the tip of the root tip sample and place on a slide.
  5. Add a few drops of stain to make chromosomes visible.
• State the formula for the mitotic index.

  Mitotic index =

  Number of cells with visible chromosomes /

  Number of cells in sample
• State the hazards and precautions for reagents used in this procedure.

  HCI - corrosive, avoid contact with skin, wear eye protection

  Toluidine Blue O stain - irritant, avoid contact with skin, wear eye protection

  Scalpel - cut away from fingers