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10 min 10 question Quiz

10 min 10 question Quiz. Do Now: Come in quietly Start your quiz. What is the cell cycle?. Do now: List the phases of the cell cycle. The Cell Cycle. Composed of 4 phases G1(gap 1) S (DNA replication /Synthesis) G2 (gap 2) M (Mitosis and cytokinesis ). Interphase. Mitotic phase.

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10 min 10 question Quiz

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  1. 10 min 10 question Quiz Do Now: Come in quietly Start your quiz

  2. What is the cell cycle? Do now: List the phases of the cell cycle

  3. The Cell Cycle Composed of 4 phases • G1(gap 1) • S (DNA replication /Synthesis) • G2 (gap 2) • M (Mitosis and cytokinesis) Interphase Mitotic phase Aim: What is the cell cycle?

  4. G1 and G2 • Phases of cell growth, differentiation (modification of cell to perform particular functions) and cell activity. Aim: What is the cell cycle

  5. S (DNA synthesis) • Copies of DNA needed for cell division are made in this phase. (DNA Replication) Aim: What is the cell cycle

  6. G0 • Cells that stop growing and dividing leave the cell cycle and enter this phase • Do you know of any cells that stop dividing? Http://www.youtube.com/watch?v=P9ngTBG2e0E • They are still metabolically active (continue doing all the chemical processes they need to survive) and viable (alive and useful) Aim: What is the cell cycle

  7. M (Mitosis and Cytokinesis) • Mitosis-nuclear division • Cytokinesis-division of the cell’s cytoplasm. At the end of mitosis and during cytokineses chromosomes uncoil and DNA starts directing protein synthesis Aim: What is the cell cycle

  8. Continual proliferation • If a cell that should be in G0 is not in G0 goes into continual proliferation • This means that it continues to grow and divide uncontrollably • This can lead to cancer. Aim: What is the cell cycle

  9. Initiation of Mitosis • A protein complex called MPF (mitosis promoting factor) initiates mitosis in the cell cycle • MPF is a protein factor made of 2 proteins: an oscillating protein (constantly increasing and decreasing in amount) called Cyclin B and a constant kinase called CDC2. • A kinase is an enzyme that ads a phosphate to a protein in a process called phosphorylation. • Because CDC2 only works when Cyclin B is present it is referred to as a CyclinDependant Kinase Aim: What is the cell cycle

  10. P CYCB CDC2 remains constantly and inactive in the cell There is an increase of Cyclin B Cyclin B phosphorylates CDC2(adds 2 phosphates) Aim: What is the cell cycle

  11. Steps to initiate mitosis • CDC2 remains constantly and inactive in the cell • There is an increase of Cyclin B • Cyclin B phosphorylates CDC2(adds 2 phosphates) • Another kinase then removes one of the phosphates • Mitosis starts • Cyclin B is degraded and CDC2 becomes inactive again Aim: What is the cell cycle

  12. P CYCB CDC2 remains constantly and inactive in the cell There is an increase of Cyclin B Cyclin B phosphorylates CDC2(adds 2 phosphates) Another kinase then removes one of the phosphates Mitosis starts Cyclin B is degraded and CDC2 becomes inactive again Enzyme X Aim: What is the cell cycle

  13. Cell Cycle Check Points Make sure that events have been completed before commencing the next phase. There are 3 major checkpoints • G1/S checkpoint-checks for cell size and damaged DNA. S-phase promoting factor is a protein used at this checkpoint to prepare DNA for replication. Aim: What is the cell cycle

  14. Cell Cycle Check Points • G2/M checkpoint-checks for proper and complete DNA synthesis/replication and damaged DNA. • M checkpoint-checks spindle fibers formation and attachment to chromatids Aim: What is the cell cycle

  15. M G1/S G2/M Aim: What is the cell cycle

  16. Apoptosis • G1/S check detects too much DNA damage the cell might selfdestruct. • Apoptosis is programed cell death • However, if among the damaged DNA is the p53 the call cannot selfdestruct ensuring cancer. • This gene has been linked to colon, breast, lung and many other cancers. Aim: What is the cell cycle

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