cell cycle and mitosis organization of the process of cell division!

Cell Cycle and Mitosis

Organization of the process of cell division!

“Omnis cellula e cellula”

Rudolf Virchow

1855

Types of Cell Division

• Binary Fission– Prokaryotic Cell

Division

• Mitosis– Eukaryotic Cell

Division

• Meiosis– Production of sex cells

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Do all cells divide?

• Cells that divide– Stem Cells

– Glial cells in the brain

– Skin cells

– Cancer cells

• Cells that don’t really divide (senescence)– Red Blood Cells

– Neurons

– Heart Cells

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Why might a cell need to divide?• Embryonic Development• Repair Tissues• Cells have a max surface area to volume ratio• Asexual reproduction• Cancer

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Cell Cycle in Eukaryotes

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What is the meaning of mitosis?

• Interphase

• Mitosis

• Cytokinesis

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How is the genetic material organized

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How does the cell change during the cell cycle?

• Are the stages discreet or continuous?

• What is important about metaphase?

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How are changes in genetic material detected?

• Changes in nuclear material first detected by dark stain of the nuclear material = “Chromo”

• Advances in light microscopy show role of centrosomes, spindle fibers, kinetochores

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Phases of mitosis

• See pg 232

• Note activity of chromosomes, envelope, spindle during each stage

• Chromosome “walking”

• Review: Biovisions video

What tells a cell to divide?• External Controls

– Growth Factors

• Internal Controls– Cyclins– CDK

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What proteins control cell growth internally?

• CDK: always present in cells• Cyclin: level varies throughout the cell cycle• MPF: “mitosis promoting factor” --occurs when

cyclin binds to CDK.

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How does cyclin’s

structure allow for its function of promoting

mitosis?

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Cancer

• Cancer is when the cell cycle goes wrong.

• What might happen to cause a cell cycle to wreak havoc?

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