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How are elephants able to grow to such a large size?

How are elephants able to grow to such a large size?. Why do animals shed their skin?. The process of mitosis begins after a sperm fertilizes an egg.

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How are elephants able to grow to such a large size?

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  1. How are elephants able to grow to such a large size?

  2. Why do animals shed their skin?

  3. The process of mitosis begins after a sperm fertilizes an egg.

  4. Three reasons why somatic cells (all body cells except sex cells) reproduce by mitosis: 1. Growth 2. Repair 3. Replacement

  5. The Cell Cycle http://www.cellsalive.com/mitosis.htm • Interphase • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis

  6. Interphaseoccurs before mitosis begins • G1 (Gap 1) phase – Cells grow to a mature size. • S (Synthesis) phase – DNA is copied. The number of chromosomes double. • G2 (Gap 2) phase – Cells prepare for cell division. CELL MEMBRANE Nucleus Cytoplasm

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

  8. Prophase -1st step in Mitosis • Cell division begins. Chromatin condenses and changes form into rod shaped chromosomes. • Centriolesappear and move to opposite poles. • Spindle fibers form around the centrioles. • The nuclear membrane and the nucleolus break down. Centrioles Sister chromatids Spindle fibers

  9. Anatomy of a Chromosome • Each chromosome was duplicated during the • S phase of interphase. The two copies are now joined at the center. This area is called the centromere. • Each half is referred to as a chromatid. The two together are sister chromatids.

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

  11. Metaphase- 2nd step in Mitosis • Sister chromatids attach to the spindle fibers at the centromere. • Centrioles are attached to the other end of the spindle fiber. • Sister chromatids move and line up at the middle or equator of the cell. Centrioles Spindle fibers

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

  13. Anaphase 3rdstep in Mitosis • Sister chromatids separate at the centromere and begin to move to the opposite poles. Centrioles Spindle fibers

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

  15. Telophase4th step in Mitosis • Two distinctive cells begin to form. • Two new nuclei form. • Chromosomes transform back to chromatin (threads rather than rods). • Mitosis ends. Nuclei Nuclei Chromatin

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

  17. Cytokinesisoccurs after mitosis • Cell membrane pinches in to create two daughter cells – each with its own nucleus with identical chromosomes. • The pinched area is referred to as the cleavage furrow in animal cells. • In plant cells, a cell plate forms instead to form a cell wall and separate the two new cells.

  18. Animal Mitosis -- Review

  19. Plant Mitosis -- Review

  20. IPMATC REMEMBER! • Interphase • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis IPlayMore AtThe Court

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