1. Controls of Cell Cycle

2. Pair-Share
Why is it important that the cell cycle is controlled?

3. 2 Types of Control:
External Control—Molecules imbedded in cell membranes signal cells to stop dividing when cells are touching.

4. Internal Control—proteins called cyclins will stop cell division before it enters each new phase if the cell is not ready to proceed.

5. Loss of Control of Cell Division
Cancer!!
Tumor—mass of cells produced by uncontrolled cell division. These cells are
typically not functional.
Malignant tumor—
damaged cells can enter
the bloodstream and
spread to other areas of
the body.

6. Exit Ticket What does “mitosis” mean?
Why is it important that cell division is controlled?
What is a tumor?
Explain how a cut in your skin would heal in terms of cell division. How do the cells “know” when to stop dividing?