Cell Cycle and Dividing Cells Number

Science 9-Biology

Observing Cell Division Lab

Purpose: To use the microscope to observe and sketch plant cells and animal cells in various stages of the cell cycle.

Equipment and Materials:

Compound Microscope Laptops Prepared Slide of Onion (Allium) Root Tips Prepared Slide of Whitefish Mitosis BC Science 9 Text pg. 162-163

Part 1-Plant Cells

Procedure:

1. Take a prepared slide of an onion tip root and observe it under low power (40X). Move the slide around until you have a section near the tip that is in clear focus. Now, increase the power of magnification (400X). Select an area and count out about 100 cells (approximately). Notice if the cells are: a) Dividing (chromosomes visible, no nucleus), b) Not dividing (nucleus visible, no chromosomes)

Fill in the following table:
|Out of about 100 cells: |
|Number of Dividing Cells |Number of Cells Not Dividing |
| | |
| | |

At any one time are most cells dividing or not-dividing? ___________________________

Look at the diagram of a plant cell

undergoing cytokinesis. Notice the thin layer of membrane in the center. This is called the Cell Plate.

Can you see any cells that appear as if they are undergoing cytokinesis?

________________________________

2. The following diagram shows onion root tip cells in the various stages of mitosis. Study these pictures.

If you need to look at more images of mitosis in onion root tips, log on to a computer and go to the