Core practical 3: Observe mitosis in root tips

Area of actively dividing cells

Meristem

Each cell has only ______ chromosomes,
so it is relatively easy to see the chromosomes once they have condensed

8

Plant cells are glued together by

A middle lamella of pectins

Use ____ to break down the pectins that hold the cell together

Hydrochloric acid

Stains the chromosomes dark red and fix the cells, stopping mitosis.

Arcetic orcein

Lids should _______ to prevent the ejection of liquid when
heating.

Have a pin-prick hole, or be slightly loose if they are screw caps

why is the root tip heated with acid

To break up the tissues into individual cells

What effect will maceration and pressing the slide preparation have on the dividing cells?

Pressing the preparation will separate the cells in the meristem tissue into individual cells in a
single layer. This makes it easier to see the chromosomes and to identify the stages of division.

What information do the cell counts give you about each stage of mitosis?

The cell counts show the relative duration of each stage in the cell cycle. The longer a phase,
the more cells are likely to be going through that phase at any point in time.

What is the role of mitosis in the life of an organism?

Mitosis produces identical daughter cells for growth, replacement and repair