Question

dentify all the false statements. 1. CDK's confer target specificity to cyclin / CDK activity. 2. Cyclins activate CDKs. 3. Only one cyclin is required per cell cycle. 4. CDK's are destroyed by the ubiquitination apparatus. 5. The concentration of a CDK changes less than a cyclin during a cell cycle.

Answer 1

Only 3rd statement is false

Explanation:

1. CDK's confer target specificity to cyclin/CDK activity-This statement is true because in the cell cycle cyclin-dependent kinases (Cdks) process signals that lead to cell division
2. Cyclins activate CDKs-This statement is true because cyclin is the regulatory subunit which binds to CDKs and activate them
3. Only one cyclin is required per cell cycle-This statement is false because there are many types of cyclins per cell cycle;for example G1 cyclins(Cyclin D and E),S phase cyclins(Cyclin A) and mitotic cyclin(Cyclin B)
4. CDKs are destroyed by the ubiquitination apparatus-This statement is true because degradation of CDKs occurs through polyubiquitination
5. The concentration of a CDK changes less than a cyclin during a cell cycle-This statement is true because during the cell division cyclins are periodically synthesised whereas CDKs concentration remains constant