CELL DIVISION
CELL DIVISION AND CANCEROUS CELLS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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G1
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G2
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end of mitosis
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all the choices
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Detailed explanation-1: -G1 checkpoint is near the end of G1 (close to the G1/S transition). G2 checkpoint is near the end of G2 (close to the G2/M transition). Spindle checkpoint is partway through M phase, and more specifically, at the metaphase/anaphase transition.
Detailed explanation-2: -These areas include the G1/S transition, where most cancer‐related defects occur, the G2/M checkpoint and its activation in response to DNA damage, and the spindle checkpoint.
Detailed explanation-3: -Cell cycle checkpoints are surveillance mechanisms that monitor the order, integrity, and fidelity of the major events of the cell cycle. These include growth to the appropriate cell size, the replication and integrity of the chromosomes, and their accurate segregation at mitosis.
Detailed explanation-4: -Checkpoint proteins, such as PD-L1 on tumor cells and PD-1 on T cells, help keep immune responses in check. The binding of PD-L1 to PD-1 keeps T cells from killing tumor cells in the body (left panel).