The free energy released by ATP hydrolysis can be used to drive endergonic reactions, such as the conversion of glutamic acid to glutamine. As you saw in the video, the synthesis of glutamine from glutamic acid is a two-step process: 1. ATP phosphorylates glutamic acid. 2. Ammonia displaces the phosphate group, forming glutamine. How does the phosphorylation of glutamic acid (Glu) provide energy for the rest of the reaction to occur? A. The addition of a phosphate to Glu forms ADP, which is then hydrolyzed, releasing energy for the reaction.B. The addition of a phosphate to Glu breaks apart a water molecule, and the oxygen is burned for energy for the reaction. C. The addition of a phosphate to Glu forms a phosphorylated intermediate with more free energy than Glu. The ammonia can thus displace the phosphate in an exergonic reaction. D. The addition of a phosphate to Glu forms a phosphorylated intermediate with less free energy than Glu. The ammonia can thus displace the phosphate in an endergonic reaction.

C. The addition of a phosphate to Glu forms a phosphorylated intermediate with more free energy than Glu. The ammonia can thus displace the phosphate in an exergonic reaction.

Explanation:

The synthesis of glutamine from glutamic acid is a two-step process catalyzed by the enzyme glutamine synthetase.

In the first step, ATP is hydrolysed into ADP and a phosphate group which is transferred to the glutamic acid to form an acyl-phosphate intermediate, γ-glutamyl phosphate, thereby raising its free-energy content.

In the second step, the acyl-phosphate intermediate, γ-glutamyl phosphate, reacts with ammonia which displaces the phosphate group in an exergonic reaction.