1. Cellular Growth
Ch 9.1

2. Surface Area To volume Ratio
Surface Area to volume ratio limits size
As surface Area Doubles the Volume increases by 4 times!
Makes large
Cells less
efficient

3. Why do cells need to be efficient?
Transportation:
Diffusion over large distances is inefficient and slow
Small size helps maintain transportation of substances

4. Why do cells need to be efficient
Communication:
Small cells are able to communicate cellular instructions better than large cells.
Signal molecules move throughout the cell

5. The Cell cycle A cycle of Cells growing and then dividing
When a cell grows too large it divides into two cells.
Division is how cells reproduce

6. Steps of Cell cycle
Interphase – Cell Grows, carries out cellular functions and replicates DNA. Longest Step of cell cycle
Mitosis – Nucleus and DNA is divided
Cytokinesis – Cytoplasm is divided creating 2 daughter cells

7. Interphase The first stage of interphase is G 1
The Cell grows and functions normally.

8. Interphase
The second stage is S
The Cell copies it’s DNA.

9. Interphase The last stage of interphase is G 2
The Cell prepares for division

10. Copy the questions to your notes!
What limits Cell size?
2. What are the three steps of the cell cycle
3. Which step is the longest?
4. What are the three phases of Interphase?
Surface area to volume ratio
Interphase, Mitosis, Cytokinesis
Interphase
G1, S, G2

11. Mitosis and Cytokinesis
Chapter 9.2

12. Mitosis
Division of the nucleus resulting in 2 identical daughter cells.
Usually followed by cytokinesis the division of the cytoplasm.

13. Genetic Material Chromatin – The DNA in the nucleus (looks stringy)
Chromosome – A single DNA molecule, visible as a bar-like structure during cell division. (human = 46 chromosomes)

14. Four stages of Mitosis (PMAT)
Prophase
Metaphase
Anaphase
Telophase

15. Prophase Chromatin condenses to chromosomes
Nuclear Membrane and nucleolus disappear
Centrioles migrate to poles
Spindles form

16. Metaphase Spindles attach to chromosomes
Chromosomes line up along the middle of the cell

17. Anaphase
Sister chromatids separate
Chromosomes move toward the poles

18. Telophase Chromosomes arrive at poles
New nuclear membrane begins to form
Spindles disassemble

19. Cytokinesis
Animals – microfilaments wrap around cytoplasm and pinch it to separate.
Plant – a new structure called a cell plate forms to divide the two cells.

21. Copy the question to your notes!
1. How many chromosomes do humans have?
2. Before Chromosomes condense during mitosis they are stringy and called _______________.
3. What are the four stages of mitosis?
4. What happens after mitosis is finished? 46
Chromatin
Prophase, Metaphase,anaphase,Telophase
cytokinesis

22. Normal Cell cycle
The cycle has built in checkpoints that monitor the cycle and can stop it if something goes wrong.

23. Abnormal Cell cycle: Cancer
Cancer is uncontrolled cell growth and division
Cancer cells can crowd out normal cells and kill an organism.
Cancer cells do not
grow like they should.

24. Causes of Cancer Genetics
Changes during cell cycle regulation are due to DNA mutation
Inherited genes
Genes getting old
Environmental effects
Carcinogens cause cancer
Examples: Tobacco, Ultraviolet radiation

25. Apoptosis Apoptosis is programmed cell death
Cells shrink and shrivel in a controlled way.

26. Stem cells
Unspecialized cells that can develop into specialized cells under the right conditions.

27. Copy the questions to your notes!
What is built in to monitor the cell cycle?
Uncontrolled cell growth is called ____________.
Programmed cell death is called ____________.
These cell are unspecialized and can turn into specialized cells in the right environment.
Check points
Cancer
Apoptosis
Stem cells