1. Slide 1 of 38 Copyright Pearson Prentice Hall Cell Division

2. Slide 2 of 38 Cell Theory Cells are the basic unit of structure for all living organisms, and all cells come from other cells. Copyright Pearson Prentice Hall

3. 10-2 Cell Division Slide 3 of 38 Copyright Pearson Prentice Hall In eukaryotes, cell division occurs in two major stages. The first stage, division of the cell nucleus, is called mitosis. The second stage, division of the cell cytoplasm, is called cytokinesis.

4. 10-2 Cell Division Slide 4 of 38 New cells are identical to old ones 1.Instructions for making new cells are found in the DNA 2.When DNA is replicated, the new cell gets the exact copy of the DNA. 3.We say that the “parent” cell produces 2 identical “daughter” cells. Copyright Pearson Prentice Hall

5. 10-2 Cell Division Slide 5 of 38 Copyright Pearson Prentice Hall Chromosomes Genetic information is passed from one generation to the next on chromosomes. Before cell division, each chromosome is duplicated, or copied. 1.Called chromatin when not dividing 2.Duplicated chromosomes are called chromatids

6. 10-2 Cell Division Slide 6 of 38 Copyright Pearson Prentice Hall Chromosomes Each chromosome consists of two identical “sister” chromatids. Each pair of chromatids is attached at an area called the centromere. Sister chromatids Centromere

7. 10-2 Cell Division Slide 7 of 38 Chromosomes How many chromosomes are in the nucleus? 1.Humans have 23 pairs or 46 chromosomes. 2.Karyotype- a picture of chromosomes where they are arranged by size and pair. a.First 22 pairs are called autosomes b.Last pair is called sex cells i. female= XX ii. Male = XY Copyright Pearson Prentice Hall

8. 10-2 Cell Division Slide 8 of 38 Copyright Pearson Prentice Hall Chromosomes When the cell divides, the chromatids separate. Each new cell gets one chromatid.

9. 10-2 Cell Division Slide 9 of 38 Mitosis Mitosis- the division of the nucleus 1.Is the process body cells reproducing asexually 2.Has 4 stages Prophase, metaphase, anaphase and telophase. Copyright Pearson Prentice Hall

10. 10-2 Cell Division Slide 10 of 38 Copyright Pearson Prentice Hall The Cell Cycle The cell cycle is the series of events that cells go through as they grow and divide. Interphase is the period of growth that occurs between cell divisions.

11. 10-2 Cell Division Slide 11 of 38 Copyright Pearson Prentice Hall The Cell Cycle During the cell cycle: a cell grows prepares for division divides to form two daughter cells, each of which begins the cycle again

12. 10-2 Cell Division Slide 12 of 38 Copyright Pearson Prentice Hall The Cell Cycle The cell cycle consists of four phases: G 1 (First Gap Phase) S Phase G 2 (Second Gap Phase)

13. 10-2 Cell Division Slide 13 of 38 Copyright Pearson Prentice Hall Events of the Cell Cycle During G 1, the cell increases in size or cell growth

14. 10-2 Cell Division Slide 14 of 38 Copyright Pearson Prentice Hall Events of the Cell Cycle During the S phase, DNA synthesis

15. 10-2 Cell Division Slide 15 of 38 Copyright Pearson Prentice Hall Events of the Cell Cycle The G 2 Phase (Second Gap Phase) Growth and centrioles are formed

16. 10-2 Cell Division Slide 16 of 38 Copyright Pearson Prentice Hall Cell Cycle Events of the Cell Cycle

17. 10-2 Cell Division Slide 17 of 38 Copyright Pearson Prentice Hall Mitosis What are the four phases of mitosis?

18. 10-2 Cell Division Slide 18 of 38 Copyright Pearson Prentice Hall Mitosis Biologists divide the events of mitosis into four phases: Prophase Metaphase Anaphase Telophase

19. 10-2 Cell Division Slide 19 of 38 Copyright Pearson Prentice Hall Mitosis

20. 10-2 Cell Division Slide 20 of 38 Copyright Pearson Prentice Hall Section 10-2 Prophase Spindle forming Chromosomes (paired chromatids) Centromere Click to Continue Mitosis Prophase

21. 10-2 Cell Division Slide 21 of 38 Copyright Pearson Prentice Hall Mitosis Prophase 1. Chromatin turns into chromosomes. 2.Nuclear membrane starts to disappear 3. Spindle starts to appear Spindle forming Centromere Chromosomes (paired chromatids)

22. 10-2 Cell Division Slide 22 of 38 Copyright Pearson Prentice Hall Mitosis Chromatin- uncoiled chromosomes. They are long strands of DNA

23. 10-2 Cell Division Slide 23 of 38 Copyright Pearson Prentice Hall Centriole Spindle Mitosis Click to Continue Metaphase

24. 10-2 Cell Division Slide 24 of 38 Copyright Pearson Prentice Hall Mitosis Metaphase. The chromosomes line up on the equator or the middle of the cell Centriole Spindle

25. 10-2 Cell Division Slide 25 of 38 Copyright Pearson Prentice Hall Individual chromosomes Anaphase Mitosis Anaphase

26. 10-2 Cell Division Slide 26 of 38 Copyright Pearson Prentice Hall Mitosis Anaphase The sister chromatids separate into individual chromosomes. Individual chromosomes

27. 10-2 Cell Division Slide 27 of 38 Copyright Pearson Prentice Hall Nuclear envelope reforming Telophase Mitosis Telophase

28. 10-2 Cell Division Slide 28 of 38 Copyright Pearson Prentice Hall Mitosis Telophase 1. Chromosomes unwind 2. Spindle disappears 3. Nuclear membrane reappears

29. 10-2 Cell Division Slide 29 of 38 Copyright Pearson Prentice Hall Cytokinesis

30. 10-2 Cell Division Slide 30 of 38 Copyright Pearson Prentice Hall Cytokinesis During cytokinesis, the cytoplasm pinches in half. Each daughter cell has an identical set of duplicate chromosomes.

31. 10-2 Cell Division Slide 31 of 38 Copyright Pearson Prentice Hall Cytokinesis In plants, a structure known as the cell plate forms midway between the divided nuclei. Cell wall Cell plate

32. 10-2 Cell Division Slide 32 of 38 Copyright Pearson Prentice Hall Cytokinesis The cell plate gradually develops into a separating membrane. A cell wall then begins to appear in the cell plate.

33. - or - Continue to: Click to Launch: Slide 33 of 38 Copyright Pearson Prentice Hall (must have QuickTake software installed on the computer you are using for this presentation) - or -

34. Slide 34 of 38 Copyright Pearson Prentice Hall The series of events that cells go through as they grow and divide is called a.the cell cycle. b.mitosis. c.interphase. d.cytokinesis.

35. Slide 35 of 38 Copyright Pearson Prentice Hall The phase of mitosis during which the chromosomes line up across the center of the cell is a.prophase. b.metaphase. c.anaphase. d.telophase.

36. Slide 36 of 38 Copyright Pearson Prentice Hall Cytokinesis usually occurs a.at the same time as telophase. b.after telophase. c.during interphase. d.during anaphase.

37. Slide 37 of 38 Copyright Pearson Prentice Hall DNA replication takes place during the a.S phase of the cell cycle. b.G 1 phase of the cell cycle. c.G 2 phase of the cell cycle. d.M phase of the cell cycle.

38. Slide 38 of 38 Copyright Pearson Prentice Hall During mitosis, “sister” chromatids separate from one another during a.telophase. b.interphase. c.anaphase. d.metaphase.

39. END OF SECTION