1. Why does a cell divide? Efficiency
Smaller the cell = quicker it can work
Transport of Substances
Cellular communication
Ratio of surface area to volume

2. Other reasons for cellular division
Growth
Replace damaged cells

3. The Cell Cycle Cell reaches max size it stops growing or divides
Cells reproduce by growing and dividing = cell cycle
3 main stages of cell cycle
Interphase – cell grows, replicates DNA
Mitosis – nucleus and nuclear material divide
Cytokinesis – cytoplasm divides

5. 3 Stages of Interphase Gap 1 (G1) normal functions Synthesis (S)
Cell copies DNA
Gap 2 (G2)
Cell prepares for mitosis

6. Mitosis Cell’s DNA separates
Creates 2 identical daughter cells
Same Number of Chromosomes
4 Stages – Prophase, Metaphase, Anaphase, Telophase

7. 1. Prophase Chromatin condenses into chromosomes X – shaped
Consist of two chromatids – identical copies of DNA
Chromatids are connected at a centromere

8. 1. Prophase Nuclear membrane disappears Spindle apparatus appears
Spindle fibers, centrioles, and aster fibers

9. 2. Metaphase
Chromatids Line up at center of cell

10. 3. Anaphase
Chromatids pull apart

11. 4. Telophase Chromosomes arrive at the poles Chromosomes unwind
Two nuclear membranes begin to form
Spindle apparatus disappears

12. Cytokinesis Divides cytoplasm Animal Cells Plant Cells
Microfilaments constrict/pinch the cytoplasm
Plant Cells
Cell plate forms between two daughter nuclei
Cell walls then form on either side of cell plate

14. http://highered. mcgraw-hill

16. Cancer Uncontrolled cell division
Tumors begin with a single cell that reproduces by mitosis
Cells in tumors divide continuously
Metastasis: Process in which cells are invasive and move to other sites in the body

17. The Cell Cycle and Cancer
Benign = not cancerous
Do not invade neighboring tissue or spread
Malignant = cancerous
Readily invade neighboring tissues
May also detach and lodge in distant places – metastasis

19. Cell grows, doubles in size Chromosome duplication
G2/M checkpoint 4
Cell division
Mitosis 3
DNA repair G2 1
Cell grows, doubles in size G1 S 2
Chromosome duplication
Checkpoints in the cell cycle regulate cell division
G1/S checkpoint
Stepped Art
p. 181

20. How does it happen? Oncogenes are activated
Normal function: cell growth, gene transcription
Tumor suppressor genes are inactivated
Normal function: DNA repair, cell cycle control, cell death

21. Tumor suppressors “Guardian(s) of the genome”
Often involved in maintaining genomic integrity (DNA repair, chromosome segregation)‏
Mutations in tumor suppressor genes lead to the “mutator phenotype”—mutation rates increase
Often the 1st mutation in a developing cancer
P53 and Rb

22. Causes of Cancer Mutation: change in genetic makeup
Any agent that causes cancer is called a carcinogen and is described as carcinogenic
Infection
Viruses (EBV, hepatitis B, papilloma)
Bacteria (Helicobacter)

23. Lifestyle Risks Smoking Diet high fat and low in fruits and vegetables
Lack of exercise
Unprotected exposure to the sun, (UV) rays
Obesity
Stress
Jobs – exposed to chemicals, etc
Radiation

24. Environmental Risks Second hand smoke PCB’s Air pollution
Industrial pollution
Chemical exposures
tar from cigarettes
some foods

25. Inherited Risks Less than 15% of cancers are inherited
Some families are more susceptible to getting certain cancers
You can’t inherit cancer its just that you maybe more susceptible to getting it

26. Treatment Chemotherapy treatment
uses medicine to weaken and destroy cancer cells in the body
affects the whole body
Radiation therapy (also called radiotherapy)
high-energy rays are used to damage cancer cells and stop them from growing and dividing
local treatment; it affects cancer cells only in the treated area

27. Cancer Prevention Healthy lifestyle Exercise and proper breathing
Balanced diet
Complete rest and sleep
Water
Eating Fruit

28. Explain what happens in each step of mitosis.
Agenda for
Review mitosis (video?)
Mitosis Cell Lab

29. If a cell has 150 chromosomes how many daughter cells are created at the end of mitosis? How many chromosomes are in each cell?
Agenda for
Finish lab
Finish worksheets
Start cancer notes

30. What is cancer? Agenda for Cancer Notes Go over worksheets and lab
Cancer worksheet