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Unit 6 Review: The Cell Cycle - Coggle Diagram
Unit 6 Review: The Cell Cycle
Mitosis
There are 4 phases of Mitosis: Prophase, Metaphase, Anaphase, and Telophase
Prophase is when the nucleus breaks down and the chromosomes are now visible. The spindle fibers also begin to form and connect to the centrioles. The chromosomes also have sister chromatoids.
In metaphase, the spindle fibers attach to the centromere, and all of the chromosones line up.
In anaphase(third phase), the sister chromatids split apart and go to the opposite sides of the cell.
Finally, in telophase, the cell breaks up into 2 different cells, each with the same amount of chromids(chromosones).
Cell Cycle
In the G1 phase(first phase), this is the first growth stage of the cell. It grows all of the organelles that it requires for being an adult cell.
At the G1 checkpoint, p53 checks that the cell has all the proper organelles it needs for dividing at this stage.
In the Synthesis phase, the DNA goes through replication(which is later needed for cell division in Mitosis).
In the G2 phase, the second growth phase, the cell continues to grow before mitosis.
Mutations and Cancer Cells
Apoptosis is programmed cell death. When the cell does not have a purpose any more or is showing signs of becoming cancerous, a white marker is placed on it and apoptosis occurs.
p53 is a type of tumor suppressor gene that can activate DNA repair, trigger apoptosis, and hold the cell in the G1 phase in order to repair it.
Tumor suppressor genes are genes that put the "breaks" on the cell cycle and slow it down.
When tumor suppressor genes are mutated, the produce a "loss of function" and the cell division goes out of control.
Proto-oncogenes are genes that speed up the cell cycle.
When they are mutated, they are known as "oncogenes" which makes the cycle go unbearably fast, and cell division goes out of control.
Cyclins and CDK bind together in order to push the cell into the next phase When they are no longer needed, they break down. Cyclin's concentration goes up and down(varying from each phase), but the CDK concentration remains constant.