Question

figure 1. change in energy over the course of four chemical reactions
14 mark for review
based on the data in figure 1, which of the following most likely represents the change in energy that occurs when atp hydrolysis is coupled with the phosphorylation of a substrate?
line 4 represents atp hydrolysis, and line 1 represents phosphorylation of a substrate.
line 1 represents atp hydrolysis, and line 4 represents phosphorylation of a substrate.
line 2 represents atp hydrolysis, and line 3 represents phosphorylation of a substrate.
line 3 represents atp hydrolysis, and line 2 represents phosphorylation of a substrate.

Explanation:

ATP hydrolysis releases energy (exergonic, products have lower energy than reactants - like line 4). Phosphorylation of a substrate is endergonic (products have higher energy than reactants - like line 1). When coupled, the overall reaction is still exergonic (net energy release).

Answer:

A. Line 4 represents ATP hydrolysis, and line 1 represents phosphorylation of a substrate.