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Unit 6: Cell Cycle - Coggle Diagram
Unit 6: Cell Cycle
Mitosis
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During mitosis, the cell divides into two daughter cells in 5 different steps.
Interphase
S
During the synthesis stage the DNA from the cell is copied into two full new strands of DNA. This step is called DNA replication and is needed so the cell divides with all of its DNA.
G2
During the growth stage two, the cell grows a little bit more and produces any molecules that it needs to divide in the next step.
G1
G0/Apoptosis
After G1 the cell goes through the P53 checkpoint. If errors are detected or the cell didn’t grow properly, the cell is sent into G0 phase where it either waits for repairs to be made and continues on or (if the mistakes are too big/can’t be fixed) the cell goes through apoptosis or programmed cell death. Some cells like nerve cells spend all their life in the G0 stage.
During growth stage one, the cell grows in size and synthesizes mRNA and protein that are required for DNA synthesis.
Checkpoints
The cell has 3 checkpoints, one after G1, one after S, and one before Anaphase in mitosis. These checkpoints check for any damage or wrong coding in the DNA or cell and if this is detected they send the cell into G0.
P53
p53 is a tumor suppressor protein that checks for damage after the G1 checkpoint and is often referred to as the “guardian of the genome”.
CDK/Cyclins
CDK and Cyclins bind to each other to push the cell into the next phase of the cell cycle. CDK stay in the cell at a constant rate while Cyclin levels go up and down when the cell is ready to move on.
Cancer Mutations
Tumor Suppressor
Tumor suppressors slow the cell growth and make sure that the cell doesn’t go on to the next stage until it is fully ready.
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Chromosomes
Chromosomes are tightly condensed DNA that coils up during mitosis. They have a centromere which is in the center of the two sister chromatids where the spindle fibers attach. They also have telomeres at the ends of the tips which acts as a clock where they shorten every time the cell divides until they disappear and cause apoptosis (usually after 40-60 divisions).
The cell cycle is a series of steps that take roughly 24 hours to complete and the end product is two daughter cells. This cycle allows our cells to make new cells, heal wounds, and grow/develop. Broken up into Interphase (G1, S, G2) and Mitosis (PMAT).