2. Cell Division Mitosis replaces worn-out old cells with fresh new duplicates

3. Generates Replacements Cell divide to a. Grow (increase in size) b. Repair (cells must be replaced with they die) c. Reproduction (new offsprings) 1. Asexual reproduction (one parent) 2. Sexual reproduction (two parents Each time a cell reproduces, the new cells contain all the essential cytoplasm, organelles, and chromosomes needed for an organism to develop, survive, and function.

4. CELL GROWTH

5. The cell cycle describes the series of phases that leads to cell division

6. First Growth Phase (G1) Interphase – part of the cell cycle that occurs between divisions G1, S, G2 G1: The cell’s primary growth phase. Normal cellular functions (making proteins, getting rid of waste, etc, take place.

7. 2.Synthesis Replication (S phase) DNADNA is synthesis (S) –the cell begins preparations fordivision. Every chromosome creates an exact duplicate of itself in a process called replication Interphase – part of the cell cycle that occurs between divisions

8. Chromosome -compact X-shaped form of chromatin formed (and visible) during mitosis Chromatid - single arm of an X-shaped chromosome S- Synthesis/DNA Replication

9. Interphase part of the cell cycle that occurs between divisions (G1, S, and G2) 1.DNA appears like threadlike coils. 2.DNA coils to form Chromosomes which appear as threadlike coils (chromatin) at start. 3.Chromosomes are copied (# doubles). 4.Sister chomatids at end of this phase

10. 3. Second Growth Phase (G2) Second period of growth and preparation for cell division Interphase = G1 + S + G2 Interphase – part of the cell cycle that occurs between divisions

11. 4.Mitosis - The cell’s nucleus duplicates, then divides 5.Cytokinesis Cytoplasm divides, forming two daughter cells

13. Mitosis Creates Duplicate Cells Overview: Mitosis leads to duplicate cells

16. Interphase

17. Chromosomes condense Mitosis - 1

18. Chromosomes line up in the middle of the cell. Mitosis 2

19. Each chromosome is pulled away from its duplicate Mitosis - 3

20. New membranes form around each complete set of chomosomes and the cell divides forming two new cells called daughter cells Mitosis – 4

21. The Details: Mitosis is a four-step process

22. 1 - Prophase Centrioles move to opposite poles of the cell Mitotic spindle, microtubules forms Chromosomes condense Nuclear envelope breakdown begins

23. Early Prophase Early prophase: chromosomes begin to condense and become visible.

24. Prophase: chromosomes are rod- shaped

25. Sister chromatids line up at the center of the cell. Microtubules attach sister chromatids to opposite poles of the spindle 2 - Metaphase

26. Sister chromatids pairs are pulled apart by the spindle fibers. One full set of chomosomes goes to one side of the cell and another identical set goes to the other side. 3 - Anaphase

27. Anaphase: chromatids begin to separate and move away

28. Spindle disperse Chromosomes are in opposite ends of the cell. Nuclear membrane forms around each set of chromatid Two new cells begin to form from the same parent. 4 - Telophase

29. Telophase: an envelop will arise around the daughter nuclei

30. Cytokinesis: Cytoplasm and organelles duplicate and are divided into equal parts. The cell splits in two

31. Interphase is the time the cell spends between cell divisions, just doing its job in the body. Most of the time cells are in interphase. Interphase

32. Mitosis - Stages

36. What stage of cell division is represented here?

42. What stage of cell division does the cell spend most of its time in?

43. What stage of cell division is represented by the cell at A?

44. What stage of cell division is represented by the cell at B?

45. What stage of cell division is represented by the cell at C?

46. What stage of cell division is represented by the cell at D?

47. What stage of cell division is represented by the cell at E?

48. What stage of cell division is represented here?

55. What structure is represented by A?

56. What cell organelle is found at A?

57. What term do we call the thread- like structures at B?

58. Meiosis I

59. Meiosos II

60. www.cancerquest.org/printfriendly.cfm?printsub=39

64. Growth, Repair and Reproduction Growth - is the result of cells producing new cells through cell division The number of cells making up the organism increases, and The organism grows.

65. Chromosomes line up in the middle of the cell. Spindle fibers (microtubules) connect centrioles to chromosomes 3 rd :Metaphase

66. Metaphase - chromosomes alined in central plane