2. Intro to topic 3 Notes

3. There are 2 reasons cells divide rather than grow indefinitely. 1. The larger that cells become, the more demand the cell places on the DNA 2. the large the cell becomes the more trouble the cell has moving enough nutrients and wastes across the cell membrane

4. Cell division is The process of DNA replication and the division of the cytoplasm to form 2 new identical cells

5. Cell division reduces the volume, and increases the ratio between volume and surface area. you will need to be able to calculate surface area, volume and the ratio of surface area to volume

6. http://www.youtube.com/watch?v=pv_- RWaADwk&feature=related&safety_mode=true&pe rsist_safety_mode=1&safe=active Hw: Do Worksheet on cell growth

7. Cell Division Chromosomes are not visible in most cells, except during ________________ Cell division When chromosomes become visible they consist of _________________ _________________ _________________ _____ 2 sister chromatids connected at the centromere

8. Each pair of chromatids is attached at an area called the ___________________________ centromere

9. The Cell Cycle is diagramed below:

10. The period of growth between cell divisions is called ______________________________ Interphase The division of the nucleus during the M phase of the cell cycle is called ___________________. Mitosis

11. Interphase is divided into 3 phases ____________________ _____________________ ____________________ G 1 Phase S Phase G 2 Phase During the G1 phase ________________________ During the S phase ___________________ During the G2 phase _________________________ Rapid growth Replication of Chromatids Prep for mitosis (make another centriole)_

13. The 4 phases of Mitosis are: 1. Prophase -- Chromosomes become visible, nucleus and nucleolus dissolve. Centrioles move to opposite ends and form microtubules( spindle). Centrioles Microtubles/ spindle Chromosomes

14. 2. Metaphase -- Chromosomes line up across the middle of the cell Chromosomes Centrioles Microtubles/ spindle

15. 3. Anaphase -- Chromosomes migrate to the 2 ends of the cell 4. Telophase -- New nuclear membrane forms, and the cell begins to divide by cytokinesis. centrioles chromatids

16. chromosomes Two new daughter cells Interphase prophase Metaphase anaphase telophase centriole spindle chromosomes Cell membrane nucleolus centrioles chromosomes Nuclear membrane

17. In animal cells _______________________ located near the nucleus help separate the chromosomes by forming ________________________. _____________________ is the process of the cytoplasm being divided in two pieces. In pant cells a _____________________ forms midway of the cell. Centrioles Spindle fibers cytokinesis Cell plate

18. When an injury occurs the cells in the area begin to ____________________ When the injury is almost healed __________________________ __________________ are responsible for regulating the cell cycle. the rate of cell division slows divide cyclins

19. Cancer is ___________________________ ______________ Cancer cells don’t respond to signals that regulate ___________ Cancer cells form masses of cells called ___________________ Cancer cells break loose and spread throughout the ___________________ unregulated cell growth tumors body growth

20. Hw: 21 in workbook worksheet