AP BIOLOGY

Detailed explanation-1: -Phosphorylation reactions often occur in series, or cascades, in which one kinase activates the next. These cascades serve to amplify the original signal, but also improving the signal (less noise) and allowing for cross talk between different pathways.

Detailed explanation-2: -A phosphorylation cascade is used for the transduction or transmission of signals. It has three major steps-reception, transduction, and response. It is a sequence of reactions that results in the phosphorylation of different proteins. One enzyme phosphorylates the other in this chain reaction.

Detailed explanation-3: -Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because the number of molecules used is small and fixed. they counter the harmful effects of phosphatases. they amplify the original signal many-fold.

Detailed explanation-4: -Activation of protein kinases Activation frequently leads to a protein kinase cascade, resulting in the rapid amplification of extra-cellular signals.

Detailed explanation-5: -The advantages of a cascade system of phosphorylation/ dephosphorylation over simple allosteric regulation are signal amplification, greater flexibility, and greater sensitivity to the metabolic needs of an organism.