AP BIOLOGY

CELL DIVISION

CELL DIVISION AND CANCEROUS CELLS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Protein ____ are enzymes that activate or deactivate other proteins by phosphorylating them. To be active, each ____ must be attached to a ____, a protein that gets its name from its cyclically fluctuating concentration in the cell
A
cyclin, kinases, enzyme
B
enzymes, kinases, cyclin
C
kinases, kinases, cyclin
Explanation: 

Detailed explanation-1: -Protein kinases (PTKs) are enzymes that regulate the biological activity of proteins by phosphorylation of specific amino acids with ATP as the source of phosphate, thereby inducing a conformational change from an inactive to an active form of the protein.

Detailed explanation-2: -Cyclin-dependent kinase (CDK) is a positive regulator that phosphorylates other proteins when activated.

Detailed explanation-3: -Phosphorylation provides a sensitive and dynamic way to regulate protein activity, stability, protein interaction and sub-cellular localization. Global regulators are often targeted by more than one kinase, altering the expression of many genes.

Detailed explanation-4: -CDKs are a family of multifunctional enzymes that can modify various protein substrates involved in cell cycle progression. Specifically, CDKs phosphorylate their substrates by transferring phosphate groups from ATP to specific stretches of amino acids in the substrates.

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