read the article https://www.sciencedaily.com/releases/2016/12/161215143511.htm
ID: 162024 • Letter: R
Question
read the article https://www.sciencedaily.com/releases/2016/12/161215143511.htm
1. What is a cyclin-dependent kinase and how is it thought to work? (Answer not found in article – see your text book or my lecture.)
2. Why was Heinemann’s hypothesis that a metabolic oscillator might set the pace for cell division a good bet? (Hint: What does a cell need to carry out cellular work?)
3. Why was Heinemann’s choice of NADH and ATP as indicators of the metabolic oscillators an appropriate choice?
4. Under what conditions are the metabolic and cell-cycle oscillators coupled? When are they uncoupled?
Explanation / Answer
Answer:
Cyclin-dependent kinases (CDKs) are the enzymes involved in the control of the cell cycle. They drive each of the major cell cycle transition points (G1, S, G2, M), inducing downstream processes by phosphorylation of specific proteins.
How do the CDK’s function!
CDK’s are activated by cyclins, cell cycle progression is controlled by pairing of CDK’s with ‘cell phase’ specific cyclin. The classes of cyclins include G1-phase cyclins, G1/S-phase cyclins, S-phase cyclins, and M-phase cyclins.
M-phase cyclins form M-CDK complexes and drive the cell's entry into mitosis;
G1 cyclins form G1-CDK complexes and guide the cell's progress through the G1 phase; and so on.
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