1. Chapter 12: The Cell Cycle

2. What you must know: The structure of the duplicated chromosome.
The cell cycle and stages of mitosis.
The role of kinases and cyclin in the regulation of the cell cycle.

3. Cell Cycle: life of a cell from its formation until it divides
Functions of Cell Division:

4. Genome = all of a cell’s genetic info (DNA)
Prokaryote: single, ______________ chromosome
Eukaryote: more than one _______ chromosomes
Eg. Human:46 chromosomes, mouse: 40, fruit fly: 8

5. Each chromosome must be duplicated before cell division
Duplicated chromosome = 2 __________________ attached by a _____________

6. Somatic Cells vs. Gametes
_________ (2n): 2 of each type of chromosome
Divide by _________
Humans: 2n = 46
_____ cells (sperm/egg)
_________ (n): 1 of each type of chromosome
Divide by __________
Humans: n = 23

7. Phases of the Cell Cycle

8. Phases of the Cell Cycle
The mitotic phase alternates with interphase:
G1  S  G2  mitosis  cytokinesis
Interphase (90% of cell cycle)
G1 Phase: cell _________ and carries out normal functions
S Phase: _________________ chromosomes
G2 Phase: prepares for ____________________
M Phase (mitotic)
Mitosis: ______________ divides
Cytokinesis: __________________ divides

9. Mitosis: Prophase  Metaphase  Anaphase  Telophase

10. Mitosis Continuous process with observable structural features:
Chromosomes become visible (______________)
Alignment at the equator (_______________)
Separation of sister chromatids (_____________)
Form two daughter cells (__________ & _________)

11. Prophase & Prometaphase

12. Metaphase & Anaphase

13. Cytokinesis
Cytoplasm of cell divided
Animal Cells: ____________
Plant Cells: ____________ forms

14. Cytokinesis in animal vs. plant cells

15. Animal Cell Division

16. Plant Cell Division

17. Which phases of the cell cycle can you identify?

18. Bacterial cells divide by:

19. Cell Cycle Control System
Checkpoint = control point where stop/go signals regulate the cell cycle

20. Major Checkpoints G1 checkpoint (Most important!) G2 checkpoint
Controlled by cell _____, _______ factors, environment
“Go”  completes whole cell cycle
“Stop”  cell enters nondividing state (G0 Phase)
Nerve, muscle cells stay at G0; liver cells called back from G0
G2 checkpoint
Controlled by ______________________completion, DNA ________________, cell size
M-spindle (Metaphase) checkpoint
Check spindle fiber (microtubule) attachment to chromosomes at __________________ (anchor sites)

21. G1 Checkpoint

22. M-spindle Checkpoint: Mitotic spindle at metaphase
_______________ = proteins associated with DNA at centromere

23. Internal Regulatory Molecules
_________ (cyclin-dependent kinase, Cdk): protein ____________ controls cell cycle; active when connected to ___________
Cyclins: proteins which attach to kinases to ___________ them; levels fluctuate in the cell cycle

24. Internal Regulatory Molecules
MPF = maturation-promoting factor
specific ______________________ complex which allows cells to pass G2 and go to M phase

25. External Regulatory Factors

26. External Regulatory Factors
Growth Factor: ______________ released by ____________ cells to stimulate cell division
_______________________ Inhibition: crowded cells normally stop dividing; cell- surface protein binds to adjoining cell to inhibit growth
___________________ Dependence: cells must be attached to another cell or ECM to divide

27. Cancer Cells
Cancer: disorder in which cells lose the ability to control growth by _________________________to regulation.
multistep process of about 5-7 genetic changes (for a human) for a cell to transform
loses anchorage dependency and density-dependency regulation
Normal Cells
Cancer Cells

28. Tumors = mass of abnormal cells
___________ tumor: lump of cells remain at original site
_________________ tumor: invasive - impairs functions of 1+ organs (called cancer)
___________________: cells separate from tumor and travel to other parts of body

29. Cancer Prevention
Anyone can get cancer but there are ways to minimize risk:
Don’t smoke, legal or illegal (includes hookahs, chew, 2nd- hand smoke)
Use sun protection
Exercise and keep weight at ideal level
Eat 5-7 servings of fruit and veggies a day
Use screening/preventative measures-breast/testicle/mole checks
Practice abstinence or use condoms
Vaccines (eg. HPV)