1. Cell Cycle Notes

2. 4 Reasons why cells divide
Efficiency
DNA Overload
Growth
Replace Cells

3. Cell Division in Prokaryotes
Called Binary Fission
DNA is copied & cell divides

4. Cell Division in Eukaryotes
Called Mitosis
Cell Grows & Copies its DNA then divides

5. The series of events that cells go through as they grow & divide ~ The Cell Cycle

6. 2 Phases of the Cell Cycle
Interphase
“M” Phase
Includes Mitosis & Cytokinesis

7. Interphase: a growth period
G1 (Growth/Gap 1) - Cell grows in size, makes new organelles & performs assigned function; DNA is relaxed in chromatin and is not visible
S phase (Synthesis) - duplicates DNA to prepare for mitosis
G2 (Growth/Gap 2) – cell prepares for mitosis

8. Interphase

10. Vocab Terms
Chromatin DNA “scrunched up” in the nucleus & is not visible

11. Vocab Terms
Chromatin DNA “scrunched up” in the nucleus & is not visible
Chromosomecell structure that carries the genetic material; visible during mitosis

12. Vocab Terms
Sister chromatidsidentical halves of the duplicated parent chromosome
Centromerecell structure that joins the two sister chromatids of a chromosome

13. Prophase DNA organizes Nuclear membrane & nucleolus disappear.
chromatin condense into visible chromosomes (of two sister chromatids held together as a pair by a centromere.
Nuclear membrane & nucleolus disappear.
Spindle fibers form between the pairs of centrioles
Prophase

14. Prophase

15. Metaphase Chromosomes line up in the middle of the cell.
Each chromatid is attached to a separate spindle fiber by its centromere.

16. Metaphase

17. Anaphase
Sister chromatids are pulled apart to opposite poles of the cell.

18. Anaphase

19. Telophase 2 identical daughter cells are formed.
Cytokinesis occurs (the division of the cytoplasm) as the plasma membrane pinches in along the equator.
Nucleolus and nuclear membrane reappear, chromosomes begin to uncoil & relax back into chromatin

20. Telophase

21. Picture of cytokinesis
*Image courtesy Indigo Instruments. Visit indigo.com for more original content like this. Reprint permission is granted with this footer included.*

22. Plants in cytokinesis
Because plant cells have a cell wall, a cell plate forms across the cell’s equator instead of pinching in.

23. Finally…
After mitosis is complete, each new daughter cell is an identical copy of the parent cell.

24. Cell Cycle Pneumonic Interphase Prophase Metaphase Anaphase Telophase
Cytokinesis I
Put My
Apples To
Cook

25. All together now…

26. Talk to a partner: Explain the phases of Mitosis

27. Cell Cycle practice

28. Cell Cycle Video Lingering Questions….
How long does the cell spend in each phase?
What is the life span of human cells?
What happens when the cell is NOT growing or dividing?
Does the cell continue in the cell cycle indefinitely?

29. How long does the cell spend in each phase?

30. How long does the cell spend in each phase?

31. What is the life span of human cells?

32. Explain why spinal cord injuries are irreversible
Think-Pair-Share: Explain why damage to heart muscle cells are permanent
Explain why spinal cord injuries are irreversible

34. What happens when the cell is not growing or dividing?
Cell is resting

35. When cells are damaged and need repair or need to be replaced, cell will reenter the cell cycle

36. Talk to a Partner: Do Cells Grow Indefinitely?
Section 10-3
If center cells are removed, cells near the space will start to grow again.
SHOWS: Cell division
genes can be turned on
and off
Cells grow until they touch other cells

37. Controlling Cell Growth Through Gene Regulation
Cell division stops when cells touch
Can resume if space is available (injury)
Cell division stops when they cannot absorb enough nutrients

38. What happens when the genes that control cell division become damaged?
Some cells do not respond to the signals that regulate the growth
Result ~ uncontrolled cell growth: cancer
Causes of cancer:
cigarette & tobacco use
radiation exposure (X-ray & UV light)
genetics
some viruses

40. Cancer Video

41. Stem Cells Stem cells - unspecialized cells
Through cell differentiation – stem cells become specialized in structure and function
Two Types: Embryonic and Adult Stem Cells

43. Cornell Summary