試題詳解

15. Which one of the following statements is NOT true for signal transduction in the cells?
(A) The relay molecules in signaling transduction are often proteins.
(B) Many of the relay molecules are protein kinases, and they often act on other protein kinases in the pathway.
(C)The activity of a protein regulated by phosphorylation depends on the balance in the cell between active kinases and active phosphatases.
(D) Cytoplasmic protein kinases phosphorylate serine or glycine.
(E)None of the above.