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Asexual Reproduction

This text explains the process of mitosis and asexual reproduction in plants and animals, including cloning. It also discusses the differences between mitosis in plant and animal cells.

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Asexual Reproduction

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  1. Asexual Reproduction Mitosis Mitosis is the process in which the nucleus divides to form two new nuclei. After cytokinesis, 2 cells are formed that are identical to each other genetically, but 1/2 the size of the parent cell. How does mitosis differ in plants and animals? 1

  2. How do little elephants grow up to be BIG elephants?

  3. Why do animals shed their skin?

  4. . Types of ReproductionAsexual 1. one parent • 2. offspring identical to parent • 3. occurs in unicellular organisms and body cells as a part of growth.

  5. Cloning • A technique that accomplishes the same result as asexual reproduction. All offspring are identical to the parent because they carry the same genetic code as the parent. • plants - babies from spider plants are clones. • - stem rooted in water that becomes a plant is a clone.

  6. Animal Cloning • Done by removing a nucleus (with the genetic information) from a “parent” organism’s cell and inserting the nucleus into an egg cell from which the nucleus has been removed. The result is an egg that has 100% of the genetic information from a single parent. The egg cell is then implanted and develops inside of a female. • Cloning has been • accomplished in • sheep and pigs.

  7. The process of asexual reproduction in us begins after a sperm fertilizes an egg.

  8. Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. Replacement Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun. Cell that reproduce by asexual reproduction reproduce constantly.

  9. Mitosis • Mitosis is the process by which a cell’s genetic material divides to create two sets of the cell’s genetic material. The product is two cells with a full set of identical genes and chromosomes, but the daughter cells are half the size of the parent cell. • Before mitosis can occur, the genetic information in the DNA of the parent cell is duplicated exactly. During cell division one copy is distributed to each cell. • Cytokinesis follows mitosis. In cytokinesis the cell divides the organelles and cytoplasm between the two new cells.

  10. Animated Mitosis Cycle http://www.cellsalive.com/mitosis.htm • Interphase • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis

  11. Interphaseoccurs before mitosis begins • Chromosomes are copied • Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) are called sister chromatids at end of this phase CELL MEMBRANE Nucleus Cytoplasm

  12. S Phase of Interphase One chromosome 2 sister chomatids Held by a centromere

  13. Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  14. Prophase 1st step in Mitosis • Centrioles(or poles) appear and begin to move to opposite end of the cell. • Spindle fibers form between the poles. • Chromosomesshorten and thicken • Nuclear membrane and nucleoli disassemble Centrioles Sister chromatids Spindle fibers

  15. Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  16. Metaphase 2nd step in Mitosis • Chromatids (replicated chromosomes) attach to the spindle fibers at the centromere. • Chromosomes line up at the equator • Centrosome- Microtubule (spindle fibers) organizing center. Centrioles in Centrosome area equator pole Spindle fibers pole

  17. Metaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  18. Anaphase 3rdstep in Mitosis • Chromatids (replicated chromosomes) separate and begin to move to opposite ends of the cell. Centrioles Spindle fibers

  19. Anaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  20. Telophase4th step in Mitosis • Two new nuclei form. • Chromosomes appear as chromatin (threads rather than rods). • Mitosis ends. Nuclei Nuclei Chromatin

  21. Telophase Animal Cell Plant Cell Cell plate Cleavage furrow Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  22. Cytokinesisoccurs after mitosis • Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes. Animals divide by a cleavage furrow and plants divide by building a cell plate

  23. Animal Mitosis -- Review

  24. Plant Mitosis -- Review

  25. Differences between Plant and Animal Cell Mitosis

  26. Cell Cycle

  27. - Cell Division The Cell Cycle 28

  28. Stages of Mitosis

  29. Mitosis Worksheet • 11. What moves the chromatids during mitosis? ___________________________________ • 12. What anchors the spindle? ________________________________________ • 13. What are the four phases of mitosis? ___________________________________________________ • 14. How many daughter cells are created from mitosis and cytokinesis? ___________________________ • 15. During what phase does cytokinesis begin? ________________________________________ • 16. If a human cell has 46 chromosomes, how many chromosomes will be in each daughter cell? _________ • 17. If a dog cell has 72 chromosomes, how many daughter cells will be created during a single cell cycle? ______ • .....Each of these daughter cells will have how many chromosomes? ____________ • 18. The nuclear membrane dissolves during what phase? ________________________ • 19. In the cell pictured above, how many chromosomes are present during prophase? ________________ • 20. What structure holds the individual chromatids together? ______________________________

  30. Mitosis worksheet Answers • 11. What moves the chromatids during mitosis? Spindle fibers • 12. What anchors the spindle? centrioles • 13. What are the four phases of mitosis? prophase, metaphase, anaphase, telophase • 14. How many daughter cells are created from mitosis and cytokinesis? two • 15. During what phase does cytokinesis begin? telophase • 16. If a human cell has 46 chromosomes, how many chromosomes will be in each daughter cell? 46 • 17. If a dog cell has 72 chromosomes, how many daughter cells will be created during a single cell cycle? 2 • Each of these daughter cells will have how many chromosomes? 72 • 18. The nuclear membrane dissolves during what phase? prophase • 19. In the cell pictured above, how many chromosomes are present during prophase? 4 • 20. What structure holds the individual chromatids together? centromere

  31. MitosisAnimation http://www.cellsalive.com/mitosis.htm

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