Unit 4: Topic 7 - Regulation of Cell Cycle Flashcards
What are cell cycle check points?
Cell cycle checkpoints are parts of the cell cycle where the cell checks to see if it is ready to progress to the next stage of the cell cycle. If a cell doesn’t have the right conditions during a cell checkpoint, the cell will not progress to the next stage of the cell cycle. There are multiple cell checkpoints, but there are three major ones, the G1 checkpoint, the G2 checkpoint, and the spindle checkpoint.
Whar are the three major cell cycle checkpoints and what do they do?
The first significant checkpoint is the G1 checkpoint. The G1 checkpoint is the checkpoint that checks if the cell wants to initiate division. It checks for factors like size, nutrients, and molecular signals to determine if the cell should divide. The second major checkpoint is the G2 checkpoint, which comes before the M phase. The G2 checkpoint checks DNA integrity and completion to ensure that a damaged cell is not replicated. The final major checkpoint is the spindle checkpoint. This checkpoint checks to see if all the sister chromatids are correctly attached to microtubules since the separation of sister chromatids is irreversible.
What are some factors that regulate the cell cycle?
There are multipe factors that regulate the cell cycle, such as cyclins which are proteins that promote certain phases of the cell cycle, checkpoints where the cell checks if it is ready to progress with division, and other chemical messengers like hormones, etc., that promote or inhibit cell division.
How do cyclins and cyclin dependent kinases regulate the cell cycle?
Cyclins and cyclin-dependent kinases (Cdks) rely on each other to regulate the cell cycle. Each cyclin promotes a certain phase of the cell cycle. In order to do this, cyclins rely on CDKs. CDKs are enzymes that phosphorylate (add a phosphate group) certain proteins to activate them. However, in order for CDKs to function, there has to be a cyclin attached to them. In summary, cyclins regulate the cell cycle by activating CDKs that activate other proteins.
What would happen if a cell was able to bypass cell checkpoints?
The cell could become cancerous and divide rapidly since there would be no check on cell division.
What would happen if a normally functionting cell detected damaged DNA during cellular replication?
The cell would either try and fix it before progressing with replication or start apoptosis(programmed cell death) if the damage was bad enough to prevent the spread of broken DNA.
