1. Cell Cycle and Mitosis

2. Why do cells divide rather than grow bigger?
Have you ever been in a traffic jam in a small town?
Where are major traffic jams found?
As a city’s population grows, more people are moving in an out which causes traffic.
Cells are like cities:
The bigger they are, the more food, water, and waste that must move in and out to keep the cell alive.

3. Why do cells divide rather than grow bigger?
To prevent traffic jams, they will divide
Cells divide for 4 major reasons: 1. 2. 3. 4.

4. Why do cells divide rather than grow bigger?
To prevent traffic jams, they will divide
Cells divide for 4 major reasons:
1. Prevent the cell from becoming too big (prevent traffic jam)
2. To heal injuries
3. To allow the organism to grow (up)
4. To reproduce (new individuals)

5. Before we get started with the cell cycle…
Before we get started with the cell cycle…. Let’s talk about chromosomes
Chromosome: DNA - containing structure that carries genetic material from one generation to another.

6. What happens during the cell cycle?
Cell Cycle - Process of cellular reproduction, occurring in the main stages
Interphase (_______)
Mitosis (____________)
Cytokinesis (_________________)

7. What happens during the cell cycle?
Cell Cycle - Process of cellular reproduction, occurring in the main stages
Interphase (growth)
Mitosis (nuclear division)
Cytokinesis (cytoplasmic division)

8. What occurs during Interphase (the 1st step in cell cycle)
There are 3 stages during interphase:
1st Grows
2nd Duplicates DNA 46
Chromosomes 92
Chromosomes
3rd Prepares to divide

9. Interphase Up Close
First Gap phase (G1): cell growth, non-dividing cells remain in this phase
Synthesis phase (S): DNA is copied (duplicated); each chromosome now consists of 2 identical chromatids
Second Gap phase (G2): cell continues to grow and prepare to divide; microtubules are formed in the cytoplasm

10. Question 1: Which of the following is NOT a reason cells divide?
To heal injuries
To allow the organism to grow
To reproduce
To maintain homeostasis

11. Question 2:
What will happen if the cell continued to grow rather than divide?
The organism would get too big.
Food & wastes would not be able to move in & out as easily.
The surface area would increase and allow more materials into and out of the cell.
Nothing would happen.

12. What are the 3 stages of the cell cycle?
Question 3:
What are the 3 stages of the cell cycle?
Prophase, Metaphase, & Anaphase
Mitosis, Telophase, & Cytokinesis
Interphase, Metaphase, & Prophase
Interphase, Mitosis, & Cytokinesis

13. Question 4: Which of the following is NOT a stage during Interphase?
Growth (G1)
DNA replicates (S)
Prepares to divide (G2)
Mitosis (M)

14. What is Mitosis?
Mitosis: 2nd main stage of the cell cycle during which the cell’s replicated DNA divides and 2 genetically identical diploid daughter cells are produced.

15. What occurs during mitosis? (the 2nd step in cell cycle)
There are 4 stages during mitosis:
1st Prophase (pro = 1st)
2nd Metaphase
3rd Anaphase
4th Telophase (telo = end)

16. What occurs during mitosis? (the 2nd step in cell cycle)
There are 4 stages during mitosis:
1st Prophase (pro = 1st)
Nucleus disappears
Centrioles separate

17. What occurs during mitosis? (the 2nd step in cell cycle)
There are 4 stages during mitosis:
2nd Metaphase
Chromosomes line up in the middle

18. What occurs during mitosis? (the 2nd step in cell cycle)
There are 4 stages during mitosis:
3rd Anaphase
Chromosomes move apart

19. What occurs during mitosis? (the 2nd step in cell cycle)
There are 4 stages during mitosis:
4th Telophase (telo = end)
Nucleus reappears
Cytoplasm starts to separate

20. What occurs during cytokinesis? (the 3rd step (LAST) in cell cycle)
Cytokinesis: The last stage of the cell cycle, during which the cell’s cytoplasm divides, creating a new cell.
Daughter Cells

21. Question 5: Mitosis creates 4 genetically identical cells.
4 genetically different cells.
2 genetically different cells.

22. What are the 4 stages of mitosis in order?
Question 6:
What are the 4 stages of mitosis in order?
Interphase, prophase, metaphase, anaphase
Interphase, prophase, metaphase, telophase
Prophase, metaphase, telophase, cytokinesis
Prophase, metaphase, anaphase, telophase

23. Question 7: Cytokinesis Interphase Telophase Metaphase
This is the last phase of the cell cycle where the cell’s cytoplasm divides to create 2 daughter cells:
Cytokinesis
Interphase
Telophase
Metaphase