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Cell Cycle and Mitosis

Cell Cycle and Mitosis. Cells. Cells come in all shapes, sizes, and functions with life spans that vary Most cells have a expiration date What does that mean? EX: stomach cells ~3-5 days Skin cells ~2-4 weeks Red blood cells ~120 days Cells that expire get replaced.

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Cell Cycle and Mitosis

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  1. Cell Cycle and Mitosis

  2. Cells • Cells come in all shapes, sizes, and functions with life spans that vary • Most cells have a expiration date • What does that mean? • EX: • stomach cells ~3-5 days • Skin cells ~2-4 weeks • Red blood cells ~120 days • Cells that expire get replaced

  3. Some cells do not expire • Once they are damaged they have very little repair/replacement • Muscle cells • Nerve cells • Brain cells

  4. Cells are specialized • specialized cells are specially designed to perform the functions for which they are intended • (aka. cell differentiation) • Specialized cells cannot be moved to other parts of the body!

  5. Cells • Somatic cells: body cells • Skin cells, liver cells, lung cells, etc. • Gamete cells: sex cells • Sperm and egg

  6. Normal somatic cell activity • Cells function properly • Cells expire • Cells divide to replace expired cells Cell Cycle

  7. Why divide? Why not grow larger? • The larger the cell… • Difficult more nutrients in and around • Difficult removing waste • More demands on DNA • Smaller cell is more efficient

  8. Cellular Division • Cell cycle: series of events that cells go through as they grow and divide • Cell cycle consists of multiple phases: (pg 245) • Interphase- G1, S , G2 • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis MITOSIS

  9. Cell cycle • driven by activation and inactivation of cyclin-dependent kinases (CDKs) • CDKs trigger phase transitions • CDKs are small serine/threonine protein kinases • Requires help from a cyclin • Cell cycle is NOT random!

  10. CDKs and cyclin regulators

  11. Interphase • Longest phase • Involves G1(growth phase, prepares for DNA replication), S (synthesis of DNA, DNA replication), G2(checks DNA duplication, growth and prepares for division) • Centrioles form

  12. Mitosis begins • Mitosis: the division of the nucleus • PMAT • Prophase, Metaphase, Anaphase, Telophase

  13. Prophase

  14. Metaphase

  15. Anaphase

  16. Telophase

  17. Cytokinesis

  18. Cell cycle and Mitosis • Start with one cell • End with two genetically identical cells • Each cell contains 46 chromosomes (diploid, 2N)

  19. What happens when cell regulators aren’t working? Tumors and cancer can arise Benign vs malignant What does it mean if cancer metastasized? Factors that increase probability for cancer: inheritance, smoking, UV light, viruses, chemicals (drugs), etc

  20. Cells Cells come in all shapes, sizes, and functions; with life spans that vary (they have an expiration date) These cells are constantly in the cell cycle Some cells do not expire Once they are damaged they have very little repair/replacement (i.e. muscle, nerve) These cells are in the G0 phase

  21. G0 phase: cells are alive, metabolically active, but do not divide. • cells do not copy their DNA and do not prepare for cell division. • Includes: heart muscle, eyes, and brain

  22. Cells are specialized specialized cells are specific to an area and function aka: differentiated cells Specialized, mature cells cannot be moved to other parts of the body!

  23. Are all cells differentiated? No! Stem cells are non-differentiated cells What does that mean?

  24. Stem cells Not all stem cells are the same- they have different abilities: Totipotent (omnipotent) Pluripotent Multipotent

  25. Stem cells

  26. Stem cells have the ability to help… • Heart disease • Alzheimer's • Spinal cord/nervous system complications • Diabetes • Organ failure • Cancer This list is only a fraction of what stem cells could potentially cure…

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