1. Chapter 5.1 Cell Growth and Division
Biology
Chapter 5.1
Cell Growth and Division

3. Biology presentations
Show flim clip link miosis 1

4. Vocabulary Divide---to separate Duplicate—an identical copy
Double—to increase two fold
Copy—reproduction of an orignial
Example: cells DOUBLE their DNA in order to DIVIDE and create two nearly identical COPIES.

5. The cell cycle has four main stages.
The cell cycle is a regular pattern of growth, DNA replication, and cell division.

6. The main stages of the cell cycle are gap 1, synthesis, gap 2, and mitosis.
Gap 1 (G1): cell growth and normal functions
DNA synthesis (S): copies DNA
Gap 2 (G2): additional growth
Mitosis (M): includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis)
Mitosis occurs only if the cell is large enough and the DNA undamaged.

11. Cells divide at different rates.
The rate of cell division varies with the need for those types of cells.
Some cells are unlikely to divide (G0).

12. Question?
Do you think a skin cell would have a long or short G1 stage?
A skin cell would probably have a short G1 stage. Skin cells undergo a lot of wear and tear because they are exposed on the outside of the body.

13. Do cells have a limit for size?

14. Cell size is limited.
Volume increases faster than surface area.

15. Surface area must allow for adequate exchange of materials.
Cell growth is coordinated with division.
Cells that must be large have unique shapes.

16. Which has the larger ratio of surface area?
Cell 3
Which cell has the largest surface area to volume ratio?
Cell 1