THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The amount of cyclin E is greatest during the S phase.
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The amount of cyclin E is highest during G1.
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Detailed explanation-1: -The answer is that the dear in the late g 1 phase. During the space, the activity of the c d c 2 would be raised.
Detailed explanation-2: -A particular cyclin called cyclin E forms a complex with Cdk 2 (cyclin-dependent kinase 2). This complex is important for the progression of the cell from G₁ into the S phase of the cell cycle.
Detailed explanation-3: -Cyclin E/CDK2 complex mostly controls cell cycle progression and DNA replication through phosphorylation of specific substrates. Oncogenic activation of Cyclin E/CDK2 complex impairs normal DNA replication, causing replication stress and DNA damage.
Detailed explanation-4: -Formation of the cyclin/CDK complexes results in phosphorylation and activation of the CDKs. Activated cyclin/CDK complexes phosphorylate specific protein substrates that enable cell cycle progression.
Detailed explanation-5: -Cyclin E interacts with CDK2 through its Cyclin box with the PSTAIRE helix on CDK2, leading to conformational changes on the CDK2 T loop (Honda et al., 2005) (Figure 1A). Exposure of CDK2 catalytic site allows for activating phosphorylation of CDK2 Thr160 by CDK activating kinase (CAK).