試題詳解

31. Proteins give cells structure and perform most cellular tasks, thus functions of proteins could be regulated via several different ways. Which of the following descriptions about regulating protein function are CORRECT?
(A) Proteins are regulated at the level of synthesis, degradation or the intrinsic activity.
(B) Proteins are marked for degradation with ubiquitin tag and then degraded within proteasomes or lysosomes.
(C) Ubiquitination of proteins is irreversible.
(D) Phosphorylation and dephosphorylation covalently regulate protein activity.
(E) Protein activity could be regulated by controlling protein location and concentration.