1. Happy Wednesday! 10/12/2011 List the phases of mitosis in order & a sentence to describe what happens in each. Come up with a way to remember the names in order!

3. Video Clips—Mitosis! Fruit Fly MitosisFruit Fly MitosisFruit Fly MitosisFruit Fly Mitosis Plant Cell DivisionPlant Cell DivisionPlant Cell DivisionPlant Cell Division

4. Let’s Review Mitosis! Microscope SlidesMicroscope Slides

5. What phase?

7. 5.3 KEY CONCEPT Cell cycle regulation is necessary for healthy growth. The cell cycle is driven by a chemical control system that both triggers and coordinates key events in the cell cycle. The cell cycle control system is regulated at certain checkpoints.

8. Internal and external factors regulate cell division. An INTERNAL signal/factor = cell sensing the presence of chemicals (enzymes) produced inside the cell An INTERNAL signal/factor = cell sensing the presence of chemicals (enzymes) produced inside the cell An EXTERNAL signal = cell sensing the chemical (ex- growth factor) produced by other specialized cellsAn EXTERNAL signal = cell sensing the chemical (ex- growth factor) produced by other specialized cells –External factors = physical and chemical signals

9. Cells can also respond to physical signals from their environment!!!! Cells sense when they are:Cells sense when they are: –too closely packed  cell division is turned OFF! –not in contact with a surface  cell division is turned ON!

10. Check it, check it out!!! Checkpoints Control points, stop/go signals, regulate the cycle! No stimulus = OFF!!! Specific stimuli start the processes!!!

11. Carcinogens = substances known to promote cancer –Cancer treatments typically kill both cancerous and healthy cells. Ex:Ex: Tobacco smokeTobacco smoke Air pollutantsAir pollutants Some virusesSome viruses Some genes!Some genes!

12. So, What are the consequences of uncontrolled cell division?!?!?! –Sometimes cells don’t respond normally to the body’s control mechanisms & divide TOO MUCH! –Cancer! –Cells don’t respond to normal signals to shut down cell division process -Keep dividing even when no signals!!!!

13. Cancer Cells may form Tumors-- Tumors = disorganized clumps of cells!! cancer cell bloodstream normal cell –Malignant (cancerous) : –Metastasize (break away) –Spread & form more tumors, invade/attack the body –Benign : –remain clustered; can be removed

14. Cells are Sometimes Killed By... Apoptosis Programmed cell death (WOW!!) Programmed cell death (WOW!!) normal feature of healthy organisms normal feature of healthy organisms Ex -- Ex -- Signals  cells produce self- destructive enzymes Signals  cells produce self- destructive enzymes Embryos—”webbing” b/w fingers Embryos—”webbing” b/w fingers Dead (apoptosis) cell

15. Video: Cancer!

16. 5.4 Asexual Reproduction KEY CONCEPT Many organisms reproduce by cell division.

17. creation of offspring from a single parentcreation of offspring from a single parent Genetically IDENTICALGenetically IDENTICAL

18. produces 2 daughter cells genetically identical to the parent cellproduces 2 daughter cells genetically identical to the parent cell parent cell DNA duplicates cell begins to divide daughter cells

19. Budding (new organism “buds” off surface of parent) Fragmentation (splitting of parent  pieces each grow into a new organism) bud Hydra Yeast Vegetative propagation (new plant from stem or underground part on parent plant)

20. Environment determines what form of reproduction is most advantageous. –when conditions are the same & “good” b/c all offspring are genetically identical!! –All offspring can reproduce, don’t need to find a mate! –Faster –In changing conditions. –Sexual repro is the advantage then, why? –So...best of both worlds = BEST!