NEET BIOLOGY

CELL STRUCTURES AND FUNCTION

CELL CYCLE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What are the different checkpoints in order?
A
M checkpoint, G2 checkpoint, and G1 checkpoint
B
G1 checkpoint, S checkpoint, G2 checkpoint, and M checkpoint
C
G1 checkpoint and G2 checkpoint
D
G1 checkpoint, G2 checkpoint, and M checkpoint
Explanation: 

Detailed explanation-1: -Diagram of cell cycle with checkpoints marked. 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: -1: Internal Checkpoints During the Cell Cycle: The cell cycle is controlled at three checkpoints. The integrity of the DNA is assessed at the G1 checkpoint. Proper chromosome duplication is assessed at the G2 checkpoint. Attachment of each kinetochore to a spindle fiber is assessed at the M checkpoint.

Detailed explanation-3: -There exist three major cell-cycle checkpoints; the G1/S checkpoint, the G2/M checkpoint, and the spindle assembly checkpoint (SAC).

Detailed explanation-4: -M checkpoint – nuclear division setup check This checkpoint takes place during the M phase. It is also called the spindle checkpoint because the cell examines whether all sister chromatids are correctly attached to the spindle microtubules that separate them.

Detailed explanation-5: -G2/M checkpoints include the checks for damaged DNA, unreplicated DNA, and checks that ensure that the genome is replicated once and only once per cell cycle. If cells pass these checkpoints, they follow normal transition to the M phase.

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