1. Cell Cycle
Page:60

2. The process in which cells do their daily function, grow, and divide.
Cell Cycle
The process in which cells do their daily function, grow, and divide.
Two major parts:
Interphase
Mitosis

3. Factors that control cell cycle
External factors:
When a cell touches another cell it stops dividing.
Chemical signals called growth factors.
Hormones.
Internal factors
Kinases- enzymes
Cyclins- proteins

4. Interphase
You can tell a cell is in interphase because it’s DNA is in loose strands called chromatin.

5. Interphase
G1- Cells spend most of the time in this stage carrying out normal functions.
Synthesis- The cell make an extra copy of its DNA.
G2- Continues normal functions, cell growth.

6. Mitosis Part of the cell cycle when cell division actually occurs.
Made up of mitosis (division of genetic material) and cytokinesis (division of cytoplasm).
Cells divide at different rates and are different sizes.

7. DNA Chromatin- loose combination of DNA
Chromosomes- condensed continuous strand of DNA

8. Telomeres- structures made of nucleotides that limit a cell’s division.

9. Label the Chromosome

10. Prophase DNA condenses into chromosomes .
Spindle fibers grow from the centrioles.
Nucleus disappears.
Prophase

12. Spindle fibers attach to the centromere of each chromosome and move them to the cell middle.
Metaphase

14. Spindle fibers pull apart the chromosomes , making separate chromatids.
Which move to opposite sides.
Anaphase

16. Telophase Nuclear membranes forms. Chromosomes uncoil.
Cell membrane begins to pinch.
Telophase

18. Cytoplasm divides, two identical cells form called daughter cells.
Cell enters interphase
Cytokinesis

19. The Cell cycle checkpoints ensure proper division of the cell.
Each checkpoint the cell is assessed to make sure everything is normal.
Controlled by internal proteins.
Checkpoints

20. Cancer and cell division
Triggered cell death is called Apoptosis.
Cancer cells do not trigger apoptosis and continue to quickly divide. These cells can break off and end up in other locations in the body.

21. Mitosis in animal cells

22. But what about the plant cells?

23. Mitosis in Plant Cells- more next Friday

24. What Cells?
Used for the division of somatic cells (everything but the egg and sperm)

25. Cell Cycle & Reproduction
Asexual reproduction is the production of genetically identical offspring form a single parent. i.e: Bacteria & Hydra
Asexual reproduction allows organisms to reproduce faster. When conditions are favorable, being genetically identical can be good. If conditions change, their lack of genetic diversity could become a disadvantage.

26. Highlights of the Cell Cycle and Mitosis
Remember that DNA is duplicated during interphase (synthesis) so that the new daughter cell will the same number of chromosomes after mitosis.
Used for the division of somatic cells (everything but the egg and sperm)
Prophase, metaphase, anaphase, telophase
Mitosis is just one part of the cell cycle- interphase (G1, synthesis, G2) and Mitosis (mitosis and cytokinensis)

28. Cell Cycle & Reproduction
Sexual reproduction results in offspring that inherit genetic information from two parents.
Sexual reproduction is more time consuming (finding a mate, growth & development of offspring), but it provides genetic diversity, which is an advantage when conditions change.

29. Organisms have pairs or sets of chromosomes (so humans have 2 sets of 23 chromosomes)

31. Important Vocabulary
Homologous chromosome – pair of identical chromosomes
Autosomes-Chromosomes not sex determining.
Sex chromosomes- determine sex

32. 4 . Diploid – When a cell had both sets of chromosomes it is a diploid cell.=2n
5. Haploid -When a cell only has one or half set of chromosomes it is a haploid cell. n

33. Mitosis
# of divisions 1
Type of cells
somatic
Sets of chromosomes
2 (Diploid)
# of cells 2
Resulting cells:
Identical
Stages
Prophase, Metaphase, Anaphase, Telophase

34. Meiosis
Meiosis is how gametes or haploid cells divide (it is how egg and sperm cells are created). There are 2 divisions, resulting in 4 unique cells. This is the basis for gentic diversity.

35. Meiosis 1 Meiosis 1: Stages
Prophase I, Metaphase I, Anaphase I, Telophase I , Cytokinesis
Crossing Over
Exchange of segments of DNA between homologous chromosomes (During prophase 1)
Independent Assortment
Random assortment or lining up of chromosomes during metaphase 1.

36. Draw and label crossing over (pg 190)

37. Meiosis 1: Draw and label the stages of meiosis 1 (pg 174)

38. Meiosis 2
Meiosis 2
DNA
DNA is not copied between meiosis 1 and 2. This is how haploid cells are formed.
Stages
Prophase 2, Metaphase 2, Anaphase 2 and Telophase 2 , Cytokinesis
Gamete formation
There are differences between the development of egg and sperm cells.

39. Draw and label Meiosis 2 on page 175

40. Mitosis vs. Meiosis
Mitosis
Meiosis

41. Compare / Contrast Mitosis and Meiosis
# of divisions
Type of cells
Sets of chromosomes
# of new cells
Resulting cells
Stages

42. Compare / Contrast Mitosis and Meiosis
# of divisions 1 2
Type of cells
somatic
gametes
Sets of chromosomes
2 (Diploid)
1 (haploid)
# of cells 4
Resulting cells:
Identical
Unique
Stages
Prophase, Metaphase, Anaphase, Telophase
Prophase 1, Metaphase1 , Anaphase1 , Telophase1, Prophase 2, Metaphase 2 , Anaphase,2 Telophase2

43. Modeling Meiosis Activity
Working in groups of 2 (or 3 if you have 5 at your table) :
Draw 2 sets of homologous chromosomes (one set big and one set small. Have 2 colors, like this
X X xx
Draw meiosis 1 and have crossing over occur
Once I check meiosis 1, draw meiosis 2 with your chromosomes from M1. Then have me check the model.
Now combine 1 of your gametes with a gamete from the other group and have the cell divide through mitosis.
Have me check the model and then clean the table.

44. Study Guide Questions What is the cell cycle? What are the stages?
What are the stages of interphase? What happens in each?
Why does the DNA need to duplicate (double) before the cell divides?
Why is mitosis important?
Be able to identify the stages of mitosis in a diagram.
What are the stages of mitosis and what happens in each stage?
How does cancer form?
What is apoptosis?
Definition of haploid and diploid cells. Know that chromosomes come in pairs in diploid cells.
Definition of somatic cells and gametes.
Why is meiosis important?
Know the stages of meiosis and what happens in each stage.
What is crossing over and why is it important?