1. Cell Growth and Division

2. Cells perform many functions from respiration to making new cell organelles
At some point they need to divide

3. How many chromosomes does an organism have?
Bacteria – 1
Most other organisms have many more

4. When a cell divides, it must make a copy of all of its chromosomes in its nucleus

5. Cell Cycle Interphase: phase in which cells spend most of their life
Normal state of a cell, cell grows, cells does “its job,” synthesizes DNA, and prepares for division

6. Cell division Continuous process
Nerve, muscle cells no longer divide—always in interphase
Skin cells, actively divide— have more complex cell cycle

7. Mitosis
Cells divide in 2 steps: first the nucleus divides and then the cytoplasm divides
Mitosis: nucleus divides to form 2 identical nuclei

8. Mitosis
Each nucleus contains same # and type of chromosomes as the original
Cytoplasm of the parent cell then undergoes division

9. Overview of Mitosis
on.com/anim_mitosis.html
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le.htm

10. Steps of Mitosis
Interphase – not part of mitosis, nucleus is visible , chromosomes not visible, but dividing,

11. Interphase, cont. – chromosomes divide but remain attached at a region called the centromere

12. Chromatid – each piece of the replicated chromosome attached at the centromere is called a chromatid

13. Prophase – chromosomes visible – double stranded attached at the centromere, nucleolus and nuclear membrane disappear,

14. Prophase, cont. – centrioles move to opposite ends of cell, spindle fibers begin to stretch across the cell

15. Metaphase – double stranded chromosomes line up across center of cell, centromere becomes attached to a spindle fiber

16. Anaphase – centromere divides and two strands of each chromosome separate and move to opposite ends of the cell

17. Telophase – centrioles and spindle fibers start to disappear, chromosomes stretch out and become harder to see,

18. Telophase, cont. –nuclear membrane begins to form around each mass of chromosomes, new nucleolus appears in each new nucleus

19. Cytokinesis – not part of mitosis, cytoplasm separates and two new cells are formed

20. Products of Mitosis
Mitosis makes two identical cells from one division
Mitosis makes body cells

21. Animal Cells v. Plant Cells in Mitosis
Have centrioles and spindle fibers
Cytoplasm pinches in to form the new cells
No centrioles, only spindle fibers
Cell plate forms between the two new nuclei
New cell walls form along the cell plate
Animal Cells
Plant Cells

22. https://wikispaces. psu