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Mitosis: Cell Division

Mitosis: Cell Division. Terminology. DNA – made of nucleic acids, housed in the nucleus, contains genes Chromatin – long strands of DNA that are wrapped around proteins (histones) Nucleosome – the DNA/ histone complex. Why does mitosis happen?. Surface area to volume ratio

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Mitosis: Cell Division

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  1. Mitosis: Cell Division

  2. Terminology • DNA – made of nucleic acids, housed in the nucleus, contains genes • Chromatin – long strands of DNA that are wrapped around proteins (histones) • Nucleosome – the DNA/ histone complex

  3. Why does mitosis happen? • Surface area to volume ratio • As a cell grows, the volume grows faster than the surface area • Not enough space in the cell membrane to send wastes out or to bring food in • Signal is sent to the cell • An organism needs to grow • To repair damage

  4. Structure of a Chromosome • Chromosome – a structure that is made of DNA and the proteins associated with it • Chromatid – one of the 2 exact copies of the DNA – often referred to as “sister chromatids” – the 2 of them together make a chromosome • Centromere – the point where the 2 chromatids are connected together to make a chromosome

  5. Homologous Chromosomes • two chromosomes that code for the same traits. One is from mom the other is from dad

  6. Cell Cycle • Interphase • Majority of a cell’s life • Cell grows • Chromosomes duplicate • Mitosis • Creates 2 daughter cells that are identical to the parent cell • Cell division

  7. Interphase • G1 • Growth One • The cell spends most of its life • S • Chromosomes are duplicated • G2 • Organelles and other parts needed for cell division are duplicated

  8. Mitosis • Prophase – the chromosomes become visible – the nuclear envelope disappears – pro = first • Metaphase – the chromosomes line up in the middle of the cell • Anaphase – the sister chromatids move away from each other • Telophase – begins as chromatids reach opposite ends of the cell

  9. Cytokinesis • The cytoplasm and organelles are divided between the two sides • Plants: • A cell plate begins forming • Animals: • A cleavage furrow forms as the cell pinches inward

  10. Levels of Organization

  11. When Good Cells Go Bad! Facts about cancer • Who will develop it? • ½ of men and 1/3 of women in the U.S. will develop cancer in their lifetime • What is it? • Uncontrolled cell division • What causes the cell to keep dividing? • Failure to produce internal regulators or respond to external regulators

  12. Causes of Cancer • a.   Tobacco use – lung, mouth, esophageal, cervical cancer • b.  Asbestos – lung cancer • c.   Radiation exposure • d.  Viral infection - HPV • e.   Charred meat – colon cancer • f.     Genetic • g.   Chemical exposure • h.  UV exposure (sun or tanning bed) – skin cancer • i. Drinking more than one drink a day for women or 2 a day for men

  13. Metastatic More dangerous Cancer travels in the body Nonmetastatic Usually less dangerous Cancer does not travel Kinds of Cancer Not all cancers form tumors and not all tumors are cancerous!

  14. How does cancer spread? Pancreatic Cancer

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