AP BIOLOGY

Detailed explanation-1: -Consequently, the protein receives a phosphate group by adenosine triphosphate (ATP) hydrolysis and due to enzymatic activity of kinase. This is the mechanism for the basis of post-translational modification (PTM) formation. In addition, phosphorylation is a reversible process due to activity of phosphatase.

Detailed explanation-2: -The conversion of ADP to ATP can occur through two kinds of phosphorylation: oxidative phosphorylation and substrate-level phosphorylation. The primary difference between these two processes lies in the source of the free energy used to drive phosphorylation.

Detailed explanation-3: -Phosphorylation is important in living cells since it is through this that energy-rich molecules (e.g. ATPs) are formed. For instance, a phosphoryl group (phosphate) is added to ADP, thus forming ATP, usually catalyzed by phosphorylases and kinases.

Detailed explanation-4: -Protein phosphorylation is a cyclic process of opposing reactions. A kinase transfers the -phosphoryl group of ATP onto protein side chains and a phosphatase removes the phosphate by hydrolysis (Fig. 3). Each turn of the cycle results in net hydrolysis of a molecule of ATP (ATP + H2O = ADP + Pi).