PATHOLOGY MCQ
CELL DAMAGE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Cyclins are carbohydrates that regulate DNA replication during the mitosis phase of the cell cycle.
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Cyclins are glycoproteins that repair DNA in the beginning of cell cycle.
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Cyclins are proteins that regulate when and how often a cell divides.
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None of the above
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Detailed explanation-1: -Cell cycle progression is regulated in part by the sequential activity of various cyclins. The cyclins are regulatory subunits that bind, activate and provide substrate specificity for their catalytic partner serine-threonine kinases, collectively called cyclin-dependent kinases (Cdks) (reviewed in refs. 8 and 9).
Detailed explanation-2: -Cyclin-dependent kinases In order to drive the cell cycle forward, a cyclin must activate or inactivate many target proteins inside of the cell. Cyclins drive the events of the cell cycle by partnering with a family of enzymes called the cyclin-dependent kinases (Cdks).
Detailed explanation-3: -Cyclins regulate the activity of their Cdk partners and also modulate their substrate specificity. More than 20 Cdk-related proteins and more than 11 cyclins have been identified in more complex eukaryotes, which has led to the concept that different cell cycle events are regulated by distinct cyclin-Cdk complexes.
Detailed explanation-4: -Cyclin-dependent kinases (CDKs) are protein kinases characterized by needing a separate subunit-a cyclin-that provides domains essential for enzymatic activity. CDKs play important roles in the control of cell division and modulate transcription in response to several extra-and intracellular cues.