Phosphorylation Cascades Involving a Series of Protein Kinases Are Useful

Multiple Choice

Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because

A) they are species specific.
B) they always lead to the same cellular response.
C) they amplify the original signal manyfold.
D) they counter the harmful effects of phosphatases.
E) the number of molecules used is small and fixed.