Consider the following reaction: Which parameter would NOT be affected by the addition of phosphoglycerate mutase?

Question

Consider the following reaction:  Which parameter would NOT be affected by the addition of phosphoglycerate mutase?

Quizplus · Accepted Answer

11ecba2d_0e54_dd26_a3bf_2ba35a9656d9_MD0008_00 Enzymes are biological catalysts that increase the rate of metabolic reactions. Phosphoglycerate mutase is an enzyme that catalyzes the reversible conversion of 3-phosphoglycerate (3-PG) to 2-phosphoglycerate (2-PG). The forward reaction (3-PG to 2-PG) occurs in glycolysis, and the reverse reaction (2-PG to 3-PG) occurs in gluconeogenesis. Catalysts increase reaction rates by facilitating formation of a more stable transition state between reactants and products. This enhanced stability decreases the activation energy E_a necessary for the molecules to react, allowing them to reach the energy threshold more often at any given temperature. As a result, the reaction rate increases in both the forward and reverse directions, resulting in an increased rate constant as calculated by the Arrhenius equation (Choices A, C, and D). Catalysts only stabilize the transition state of a chemical reaction. They do not stabilize the reactants or products themselves, and therefore the difference in energy between them (ΔG°) is not affected. The equilibrium constant of a reaction K_eq is the ratio of products to reactants at equilibrium, and is related to the standard free energy change by the equation ΔG° = −RT ln(K_eq). Because ΔG° does not change in the presence of a catalyst, the equilibrium concentrations of products and reactants also do not change. Therefore, the addition of phosphoglycerate mutase does not change the equilibrium concentrations of 2-PG or 3-PG. Educational objective: Catalysts, including enzymes, increase reaction rate constants by stabilizing transition states and decreasing activation energy. They do not affect the energy states of products or reactants, and therefore they do not affect the equilibrium positions of the reactions they catalyze.

Consider the Following Reaction: Which Parameter Would NOT Be