1. 2.3 The Cell Cycle and Mitosis
Take Cornell Notes on a separate sheet of paper

2. Which turtle has bigger cells?
Think About It????
Which turtle has bigger cells?

3. Which turtle has bigger cells?
Think About It????
Which turtle has bigger cells?
NEITHER! They both have the same size cells.

4. Cell Division is Essential to Life
Cell division is the only way single-celled organisms can reproduce.
Multicellular organisms need cell division to grow and to replace dead or damaged cells.
After growth stops, division remain important in normal cells. Some cells divide continuously like our skin and gut cells.
Other cells have to divide to heal wounds like skin cuts or broken bones.

5. Why don’t cells continue to grow?
There are two main reason why cells divide instead of continue to grow:
The larger the cell becomes, the more demands the cell places on its DNA
The cell has more trouble moving enough nutrients and wastes across the cell membrane.

6. DNA “Overload”
Information that controls a cell’s function is stored in a molecule knows as DNA
In eukaryotic cells, DNA is found in the nucleus

7. DNA “Overload”
When a cell is small, the information stored in the DNA is able to meet all of the cell’s needs
If a cell was too large an “information crisis” would occur and the cell would not function properly

8. Example: Small library in a large city

9. Exchanging Materials
Food, water and nutrients enter the cell through its cell membrane
Waste products leave in the same way

10. Exchanging Materials
Example: Small streets in a big town

11. The stages of a cells life cycle is called. THE CELL CYCLE
The stages of a cells life cycle is called THE CELL CYCLE. During the cell cycle the cell grows and divides producing 2 identical daughter cells. Does the cell spend most of it’s time in interphase or mitosis?

12. Interphase This is the beginning of the cell cycle
Interphase This is the beginning of the cell cycle. It is subdivided into 3 phases: G1, S and G2. During interphase, the cell is preparing for division.

13. Interphase
G1: The cell grows larger and the organelles are duplicated S: Exact copies of the DNA is made. This process is called DNA replication. G2: The DNA copies are checked for errors. Centrioles are produced.

14. Mitosis The process of cell division Mitosis follows interphase The 4 phases of mitosis can be remembered using the word: “PMAT” Prophase Metaphase Anaphase Telophase

15. The following slides will describe the 4 phases of Mitosis
The following slides will describe the 4 phases of Mitosis. Draw and label the diagrams inside of the RED boxes into your notes.

16. Mitosis
Prophase The chromatin condense into chromosomes. The centrioles begin to separate and spindle fibers form. The nuclear envelope breaks down.
Centrioles

17. Mitosis
Metaphase The chromosomes line up in the center of the cell The spindle fibers connect to the centromere

18. Anaphase The chromatid of each chromosome are pulled apart
Mitosis
Anaphase The chromatid of each chromosome are pulled apart
Chromatid

19. Mitosis
Telophase Chromosomes are separated into 2 identical sets at opposite ends of the cell. Chromatid loosen back into chromatin 2 new nuclear envelopes form

20. Cytokinesis The final step in the cell cycle
Cytokinesis The final step in the cell cycle. The cytoplasm pinches in half. 2 identical daughter cells are produced.

21. 2.3 The Cell Cycle and Mitosis
At the end of your notes create new section for a “SUMMARY” Write a paragraph to summarize the cell cycle
Mitosis

22. Copyright Pearson Prentice Hall
Quiz
The series of events that cells go through as they grow and divide is called
the cell cycle.
mitosis.
interphase.
cytokinesis.
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23. Copyright Pearson Prentice Hall
Quiz
The phase of mitosis during which the chromosomes line up across the center of the cell is
prophase.
metaphase.
anaphase.
telophase.
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24. Copyright Pearson Prentice Hall
Quiz
Cytokinesis usually occurs
at the same time as telophase.
after telophase.
during interphase.
during anaphase
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25. Copyright Pearson Prentice Hall
Quiz
DNA replication takes place during the
S phase of the cell cycle.
G1 phase of the cell cycle.
G2 phase of the cell cycle.
M phase of the cell cycle.
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26. Copyright Pearson Prentice Hall
Quiz
During mitosis, “sister” chromatids separate from one another during
telophase.
interphase.
anaphase.
metaphase.
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