2. MITOSIS

3. 1.Where do Living things come from? “Living things are reproduced from other living things of the same kind”

4. 2. What is Spontaneous Generation?

5. An INCORRECT theory that once said that living things could just appear from non-living things.

6. 3. Describe a “faulty” experiment that was used by early scientist to demonstrate this theory of spontaneous generation.

7. a) Meat was left out for the “Air” to touch. b) A few days later, maggots appeared as if by magic on the meat.

8. 4. What was wrong with this spontaneous generation experiment?

9. a) The controls were no good – The meat was left open, and anything could have gotten on it----- not just air!

10. Pop’s note! What really happened? Flys landed on the meat and laid eggs.

11. 5. When did Francesco Redi try to prove that Spontaneous generation was a fake: 1668

12. 6. Explain the experiment performed by REDI:

13. a) Redi placed a piece of meat in each of two jars.

14. b) One jar was sealed with cheesecloth so that air could get in, but nothing else could.

15. c) One jar he left open. Anything could get in.

16. d) Flys got into the open jar, but not the sealed one.

17. e) Maggots appeared on the meat in the open jar, but not on the meat in the sealed jar.

18. 7. What did redi’s experiment appear to prove?

19. The maggots were the offspring of flys…not Produced by magic.

20. 8.Did Redi’s experiment totally disprove spontaneous generation? “For the moment, but not for long.”

21. 9. What caused the debate over spontaneous generation to start up again?

22. In 1675, the world of microorganisms was discovered.

23. 10. Who finally ended the debate over spontaneous generation? “A french scientist named Louis Pasteur”

24. 11. What was Pasteur’s theory about microorganisms?

25. Pasteur believed that Sleeping bacteria were riding on the dust particles in the air. When they landed on a food source, they became active!

26. 12. Describe Pasteur’s Experiment:

27. a) Made a special flask with a “S” – shaped neck.

28. b) Put broth in each one and boiled it.

29. c) Microbes were killed in both flasks.

30. d) He tilted the flask, so no bacteria could get in from the air.

31. e) The broth stayed free of bacteria.

32. f) He stood the flask up, allowing air to enter the neck of the flask, and soon bacteria began to grow in the broth.

33. 13. What did Pasteur prove?

34. He proved that bacteria was indeed coming in from the air, not just appearing by magic.

35. 14. What is the theory of BIOGENESIS?

36. “At the present time, and under present conditions on earth, all organisms are produced from other organisms of the same kind.

37. 15. What brought about the theory of biogenesis?

38. The REDI experiments started it, then the pasteur experiments proved it.

39. 16. What role did Virchow play in the development of the cell theory and in the theory of biogenisis?

40. In 1858, Virchow, a Russian pathologist, observed cells dividing. This proved that cells come from other cells.

41. Reproduction Of Body cells

42. 17. What is a SOMATE cell?

43. Any body cell that is not a SPERM or an EGG.

44. 18. Why would an organism need to reproduce somate cells?

45. 1- GROWTH

46. 2- BODY REPAIR

47. 19. Differentiate the parent cell and the daughter cells:

48. The parent cell has enlarged and prepared itself to divide.

49. The daughter cells are the two cells that result from cell division.

50. 20. Why is it better to create many tiny cells instead of just making a few big cells?

51. The smaller the cell, the easier it is for the cell to maintain itself, like getting food and getting rid of waste.

52. 21. What is the cell cycle?

53. A twenty hour series of events that a cell goes through in order to become a parent and then to divide.

55. 22. Explain what happens at each step of the cell cycle:

56. a)mitosis: The parent cell divides into 2 daughter cells. Takes 2 hrs.

57. b)G1 phase Daughter cells get much bigger, and develop more cytoplasm Takes 4 hrs.

58. c) S phase: Cell duplicates its chromosomes Takes 10 hrs

59. d) G2 The cell creates extra organelles Takes 4 hrs Cell enters mitosis again.

60. 23. What is the difference between interphase and mitosis itself?

61. Interphase is when the small daughter cells prepare to become a parent. Mitosis is when the parent divides itself into 2 daughter cells.

62. 24. What is Chromatin?

63. Thin strands of DNA found locked away in the nucleus of a cell.

64. 25. Explain how and when a chromatin strand becomes a chromosome:

65. How? The chromatin is rolled up on a protein spool called a HISTONE.

66. When? During the S-phase of interphase

67. 26. Explain how and when a chromosome becomes a pair of sister chromatids:

68. How? Each chromosome is duplicated! The matching pair is called “Sister Chromatids”

69. When? During the S-phase of interphase

70. 27. Draw, label, and color a picture of the sister chromatids that we find going into prophase:

72. 28. Outline the steps of mitosis:

74. http://www.johnkyrk.com/mi tosis.html

75. Prophase 1- Nuclear membrane dissolves.

76. Prophase 2- Nucleolus dissolves

77. Prophase 3- Centrioles appear

78. Prophase.4- Sister chromatids Are thick and visible.

79. Metaphase 1- Centrioles move to North and south poles.

80. Metaphase 2- Chromosome pairs Line up in the middle of the cell.

81. Metaphase 3- Centrioles send down spindle fibers which attach to the centromeres of the sister chromatids.

82. Anaphase 1- Chromosome Pairs separate!

83. Anaphase 2- Spindle fibers pull the separated chromosomes towards the poles.

84. Telophase 1- Chromosomes reach the poles

85. Telophase 2- Cell membrane begins to indent and cytoplasm begins to separate.

86. Telophase 3- Complete separation has occurred!

87. Telophase 4- New nuclear membrane will form, and nucleolus will reform.

88. Telophase 5- The two new daughter cells will enter INTERPHASE

90. 29. WHAT IS MEANT BY THE RATE OF CELL DIVISION?

91. “How fast and how often specific cells reproduce themselves”

92. 30. How often do the following healthy cells reproduce themselves?

93. Blood cells? Every hour

94. Liver cells? Only as needed

95. Skeletal Muscle? When torn or injured

96. .Nerve cells? Never. It remains in interphase indefinitely.

97. .Smooth Muscle like stomach muscle? Never. It stays in interphase indefinitely.

98. 31. Explain how the rate of mitosis is associated with the following conditions:

99. Old Age: Mitosis slows down and eventually stops. The cells we have are not replaced, just allowed to wear out.

100. Cancer The speed of mitosis is too fast! The cells do not function and begin to build up into piles called TUMORS.

101. 32. Explain what has happened genetically to the people in the following pictures:

102. ? Before After

103. BeforeAfter ?

104. Their rate of mitosis has slowed down to the point that they are no longer replacing their body cells. Old cells are wearing out.

105. My little Mitosis Book

106. PROPHASE

107. 1- Nuclear membrane dissolves 2-Nucleolus dissolves