030 OBSERVING MITOSIS

A single diploid cell will divide to form 2 diploid cells. These 2 cells will each

divide into 2 cells. In time, millions of cells are produced. The division of

nuclear material in which each new nucleus obtains the same number of

chromosomes and the same nuclear code as the original nucleus is called

mitosis. Mitosis occurs in 4 phases with an inter-phase between each mitosis.

MATERIALS REQUIRED

Slides, cover slips, tap water & microscope

Cups , Forceps, Razor blade, Paper towel, or absorbent paper

Carnoy’s fluid: [Ethanol (Absolute ) 55 ml + Chloroform 45 ml]

15% Hydrochloric acid

Fresh onion root tips

Ink or saffranin

In one cup pour 15% HCl into it to cover the bottom, and in other cup pour

enough Carnoy’s fluid in it to cover the bottom. Use forceps to transfer an onion

root tip into the HCl. After 4 minutes, transfer the root to Carnoy’s fluid and

leave it for 20 minutes. Now place the root on a slide and with a blade cut off

one to two mm of the root tip for the preparation. Cover this root tip with a few

drops of ink or Saffranin for 2 minutes, blot away the excess stain. Be careful

not to touch the root tip.

Cover the root tip with one to two

drops of water put a cover slip over the

root, put a paper towel or other

absorbent paper and with your thumb

firmly press on the cover slip.

root tip

cover slip

glass slide

The majority of the cells will be in interphase.

Of the cells undergoing mitosis, the majority will be in prophase, while very few will be in metaphase, anaphase, and telophase

Observe your preparation under the

low power of a microscope.

Search the slide to find cells in various

stages of cell division, once you have

located cells in division, change to

high power & try to observe several

stages of division

prophase metaphase

anaphase telophase

interphase

A rough illustration to guide you in identification of cell division stage