1. Chapter 8: Cellular Transport and the Cell Cycle
8.2: Cell Growth and Reproduction

2. Cell Size Limitations:
Diffusion slows with distance.
Large cells can’t get enough nutrients or
rid enough waste.
Large cells have to have enough DNA to
make enough proteins/enzymes, so they
are often multinucleated.

3. Surface area = 24 mm2 Volume = 8 mm3
Surface - to - Volume - Ratio
4 mm
4 mm
1 mm
2 mm
1 mm
2 mm
1 mm
2 mm
Surface area =
6 mm2
Volume =
1 mm3
4 mm
Surface area = 24 mm2 Volume = 8 mm3
Surface area = 64 mm2
Volume = 96 mm2
As a cell’s size increases, its volume increases much faster than its surface area. Large cells cannot carry out necessary functions efficiently

4. Cell Reproduction:
All cells go through the Cell Cycle as they grow and develop.
Enzymes control this cycle.
Interphase S G2 G1
Mitosis
Cytokinesis

5. I. Interphase: Cells spend most of their life in the Interphase.
Interphase is divided into three parts:
1st is G1 : rapid growth and
metabolic activity
Interphase
2nd is S: DNA
synthesis
and replication
(DNA is copied) S G1 G2
3rd is G2: centrioles replicate in
preparation for mitosis.

6. II. Mitosis: nuclear division resulting in two
II. Mitosis: nuclear division resulting in two nuclei with exact copies of DNA.
Mitosis

7. 4 phases of mitosis: 1. Prophase Spindle fibers
Disappearing nuclear envelope
Chromosomes become visible and are double

8. called sister chromatids. They are held together by a centromere.
When chromosomes
are copied they are
called sister chromatids.
They are held together
by a centromere.
Sister chromatids

9. 2. Metaphase Centromere Sister chromatids Spindle fibers
During metaphase sister chromatids line up at the middle
of the spindle fibers. (At the equator)

10. 3. Anaphase Sister chromatids are pulled apart to opposite poles of
the cells.

11. 4. Telophase Nuclear envelope reappears
Two identical nuclei are formed

12. III. Cytokinesis: Cell division is complete when
III. Cytokinesis: Cell division is complete when cytokinesis occurs and the cytoplasm divides.

13. Review mitosis and cytokinesis:
Click
picture
to start
movie

14. Cell reproduction is complete and the cycle begins again.
Interphase S G2 G1
Mitosis
Cytokinesis

15. Cellular organization is:
Cells
Tissues
Organs
Organ Systems

16. Cancer is uncontrolled cell growth.
Causes of Cancer
Environmental factors, such as cigarette smoke, air and water pollution, and exposure to ultraviolet radiation from the sun, are all known to damage the genes that control the cell cycle.

17. Causes of Cancer Cancer Prevention
Cancer may also be caused by viral infections that damage the genes.
Cancer Prevention
Physicians and dietary experts agree that diets low in fat and high in fiber content can reduce the risk of many kinds of cancer.
Vitamins and minerals may also help prevent cancer.

18. Cancer Prevention
In addition to diet, other healthy choices such as daily exercise and not using tobacco also are known to reduce the risk of cancer.