RP2

Question 1

What is the mitotic index?

Answer 1

Ratio of cells undergoing mitosis to the whole number of cells present
Number of cells with visible chromosomes/ total number of cells present

Question 2

Method

Answer 2

Heat HCL
Cut a small sample of the root tip using a scalpel
Transfer root tip into HCL
Remove from HCL wash sample
Place in microscope slide
Add drops of stain
Lower cover slip down carefully
Place under a microscope and set the objective lens on lowest
Use the fine adjustment knob to carefully re-adjust the focus until, the image is clear
Calculate the mitotic index

Question 3

Why is a stain used?

Answer 3

To make the chromosomes easily visible and allow the cells which are undergoing mitosis to be identified

Question 4

Why must you take care when lowering the cover slip?

Answer 4

No air bubbles get in which could distort the image

Or the cover slip could slide sideways and damage the chromosomes