Why are the kinases of the cell-cycle control system known as cyclin-dependent protein kinases? What is a cyclin, and what is its role in the cell?
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Please provide a long and detailed explanation to this question:
A cellâs progression through the cell cycle requires the activity of several cyclin-dependent kinases (G1-Cdk, G1/S-Cdk, S-Cdk, M-Cdk) How are they activated, how are they inactivated, when do you see their levels rise and what are their targets? How does this activity regulate the cell cycle?
Which of the following statements concerning cyclins is not correct?
(A) They catalyze the phosphorylation of cyclin-dependent protein kinases.
(B) They are regulatory subunits for enzymes that catalyze the phosphorylation of proteins.
(C) They are activated and degraded during the cell cycle.
(D) They can become linked to ubiquitin.
(E) They contain specific amino acid sequences that target them for proteolysis.
* * Why is A wrong ? Thanks !
Different cyclin-dependent protein kinases (CDKs) regulate the transition of eukaryotic cells from one phase of the cell cycle to another: from G1 to S, S to M, or M to G1. Describe the different mechanisms by which the enzyme activity of the CDKs is regulated over time during the cell cycle and how such mechanisms are altered in different cancers. In some cells such as trophoblasts (cells of the placenta) and megakaryocytes (precursors to blood platelets), cells will undergo repeated rounds of G1 and S phase without G2 or M phases â what is the advantage of this cell cycle for such cells?