PATHOLOGY MCQ
CELL DAMAGE
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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G1
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G2
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S
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M
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Detailed explanation-1: -These studies confirm that UV is an S-phase-dependent clastogen and point to the G1 /S border as a time of maximal sensitivity to clastogenesis. Irradiation of G1 cells was shown to produce a fluence-dependent reduction in the rate of entry of cells into the S-phase.
Detailed explanation-2: -Following a low dose of UV radiation, DNA replication is inhibited and the cells undergo a transient arrest re-entering the cell cycle by 24 h. Instead, a high dose of UV damage leads to an initial replicative arrest followed by death of the cells by apoptosis.
Detailed explanation-3: -The primary G1/S cell cycle checkpoint controls the commitment of eukaryotic cells to transition through the G1 phase to enter into the DNA synthesis S phase.