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Chapter 3 cell division


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Chapter 3 cell division

  1. 1. Chapter 3 Cell Division
  2. 2. Two Types of Cells Composing the Body <ul><li>1. Somatic cells- pertains to the cell composing the bulk of the body such as the nerve cell, muscle cells, kidney cell, etc. </li></ul><ul><li>2. Germ cells – pertains to the reproductive cells such as the ova of female and the spermatocytes of male. </li></ul>
  3. 3. Types of Cell Division <ul><li>A. Mitosis - division in somatic cells and produces two identical daughter cells during prophase, prometaphase, metaphase, anaphase, and telophase. </li></ul><ul><ul><li>Consist of two phases </li></ul></ul><ul><ul><ul><li>1. nuclear division (Karyokinesis) plus </li></ul></ul></ul><ul><ul><ul><li>2. cytoplasm division (cytokinesis), </li></ul></ul></ul><ul><ul><ul><li>Interphase is often included in discussions of mitosis, but interphase is technically not part of mitosis, but rather encompasses stages G1, S, and G2 of the cell cycle </li></ul></ul></ul>
  4. 4. <ul><li>B. Meiosis – division in reproductive cells producing four daughter cells </li></ul><ul><li>Meiosis differs from mitosis in that cell division begins with a cell that has a full complement of chromosomes and ends with gamete cells , such as sperm and eggs , that have only half the complement of chromosomes. </li></ul><ul><li>When a sperm and egg unite during fertilization, the cell resulting from the union, called a zygote , contains the full number of chromosomes </li></ul>
  5. 6. <ul><li>46 Chromosomes (23 pairs) </li></ul><ul><li>1. Autosome (22 pairs) </li></ul><ul><li>2. Sex Chromosomes (a Pair) </li></ul><ul><ul><li>X chromosomes – female </li></ul></ul><ul><ul><li>XY chromosomes - male </li></ul></ul>
  6. 7. <ul><li>The human body, for example, consists of an estimated 20 to 30 trillion cells </li></ul><ul><li>Human cells also display a variety of sizes, from small red blood cells that measure 0.00076 mm (0.00003 in) to liver cells that may be ten times larger. </li></ul><ul><li>About 10,000 average-sized human cells can fit on the head of a pin. </li></ul>
  7. 8. <ul><li>Multicellular organisms use mitosis for growth, cell repair, and cell replacement. </li></ul><ul><li>In the human body, for example, an estimated 25 million mitotic cell divisions occur every second in order to replace cells that have completed their normal life cycles. </li></ul><ul><li>Cells of the liver, intestine, and skin may be replaced every few days. </li></ul><ul><li>Recent research indicates that even brain cells , once thought to be incapable of mitosis, undergo cell division in the part of the brain associated with memory. </li></ul>
  8. 9. <ul><li>Regulation of the cell cycle is accomplished in several ways. </li></ul><ul><li>Some cells divide rapidly. </li></ul><ul><li>Beans, for example take 19 hours for the complete cycle; </li></ul><ul><li>Red blood cells must divide at a rate of 2.5 million per second. </li></ul><ul><li>Liver cells will divide if part of the liver is removed. The division continues until the liver reaches its former size . </li></ul><ul><li>Some cells, such as liver cells, retain but do not normally utilize their capacity for division. </li></ul><ul><li>Others, such as nerve cells, lose their capability to divide once they reach maturity. </li></ul>
  9. 12. Cells go through two basic phases:  Mitosis, Interphase <ul><li>INTERPHASE </li></ul><ul><ul><li>G0 phase – </li></ul></ul><ul><ul><ul><li>normal cell functions </li></ul></ul></ul><ul><ul><li>G1 phase – </li></ul></ul><ul><ul><ul><li>prepares for cell division, </li></ul></ul></ul><ul><ul><ul><li>duplicates organelles, </li></ul></ul></ul><ul><ul><ul><li>centriole replication </li></ul></ul></ul><ul><ul><li>S phase – </li></ul></ul><ul><ul><ul><li>DNA replication </li></ul></ul></ul><ul><ul><ul><li>Chromosome duplication </li></ul></ul></ul><ul><ul><li>G2 phase – </li></ul></ul><ul><ul><ul><li>protein synthesis, </li></ul></ul></ul><ul><ul><ul><li>centriole replication completed </li></ul></ul></ul>
  10. 13. Karyokinesis <ul><li>1. prophase </li></ul><ul><li>2. metaphase </li></ul><ul><li>3. anaphase </li></ul><ul><li>4. telophase </li></ul>
  11. 14. Prophase
  12. 15. Prophase <ul><li>Chromosome condense into visible structures </li></ul><ul><li>Chromatin - complex of DNA and proteins </li></ul><ul><li>Sister chromatids - the two copies of the chromosome </li></ul><ul><li>Centromere becomes visible </li></ul><ul><li>Spindle fibers begin to extend from centrioles </li></ul>
  13. 16. Metaphase
  14. 17. Anaphase
  15. 18. Kinetochore Aster
  16. 19. Telophase
  17. 20. Cytokinesis <ul><li>Cytoplasmic division - cleavage furrow forms in anaphase or telophase & constricts original cell into two smaller cells </li></ul><ul><li>Each cell has a copy of hereditary information in its chromosomes </li></ul>
  18. 22. The difference between
  19. 23. Second Stage
  20. 25. Human Life Cycle
  21. 26. <ul><li>End of presentation </li></ul><ul><li>Exam next meeting! </li></ul>
  22. 32. Telophase
  23. 33. Cytokenesis
  24. 46. Interphase
  25. 48. Prometaphase
  26. 49. Metaphase
  27. 50. Anaphase
  28. 51. Telophase
  29. 52. Cytokenesis
  30. 54. <ul><li>Which of the following statements is NOT true of mitosis? </li></ul><ul><li>A. A single nucleus gives rise to two identical daughter nuclei . B. The daughter nuclei are genetically identical to the parent nucleus . C. The centromeres divide at the onset of anaphase . D. Homologous chromosomes synapse in prophase . </li></ul>
  31. 55. <ul><li>Cytokinesis in a plant cell is characterized by: </li></ul><ul><li>A. the equal division of homologous chromosomes . B. a pinching off of the cell membrane to divide the cell . C. the formation of a cell plate in the cytoplasm . D. the movement of the chromosomes from the metaphase plate </li></ul><ul><li>The first stage of mitosis when chromosomes start becoming visible in the microscope is called: </li></ul><ul><li>A. anaphase B. prophase C. telophase D. metaphase </li></ul>
  32. 56. <ul><li>Which of the following features of cell division are very different for animal and plant cells? </li></ul><ul><li>A. prophase B. metaphase C. anaphase D. cytokinesis </li></ul><ul><li>The stage of the cell cycle where each chromosome is composed of two chromatids in preparation for mitosis. </li></ul><ul><li>A. G1 B. S C. M D. G2 </li></ul>
  33. 57. <ul><li>The stage of the cell cycle where the cell is preparing to begin DNA replication is called: </li></ul><ul><li>A. G1 B. G2 C. S D. M </li></ul>
  34. 58. Meiosis – Prophase & Prometa
  35. 59. Meta & Anaphase
  36. 60. Telo & Cytokinesis
  37. 61. plant