Problem 8 - AP Psychology Premium Prep 2021

Question

The biggest difference between an enzyme-catalyzed reaction and an uncatalyzed reaction is that (A) the free energy between the reactants and the products does not change (B) the free energy difference between the reactants and the products does not change (C) the catalyzed reaction would not occur without the enzyme (D) a different amount of energy is required to reach the transition state of the reaction

Step-by-Step Solution

Answer

The biggest difference between an enzyme-catalyzed reaction and an uncatalyzed reaction is that a different amount of energy is required to reach the transition state of the reaction. Enzymes lower the activation energy needed for a reaction to occur, making reaction rates faster, while in uncatalyzed reactions, the activation energy is higher, and the reaction rates are slower. Therefore, the correct answer is (D).

Step 1: Option A: Free energy between the reactants and the products does not change

Both enzyme-catalyzed and uncatalyzed reactions follow the first law of thermodynamics, which states that energy cannot be created nor destroyed, only transformed. Therefore, the free energy between both reactants and products does not change in both cases.

Step 2: Option B: Free energy difference between the reactants and the products does not change

Similarly to option A, the free energy difference between reactants and products remains the same in both enzyme-catalyzed and uncatalyzed reactions. Both types of reactions follow the same energy principles, so the overall energy difference does not change.

Step 3: Option C: The catalyzed reaction would not occur without the enzyme

In enzyme-catalyzed reactions, enzymes act as catalysts that speed up the reaction. However, the reaction can still occur without the enzyme, albeit at a significantly slower rate. This statement is not entirely accurate, as the catalyzed reaction can still happen without the enzyme, but with less efficiency.

Step 4: Option D: A different amount of energy is required to reach the transition state of the reaction

The most significant difference between enzyme-catalyzed and uncatalyzed reactions is the amount of energy required to reach the transition state, known as the activation energy. Enzymes lower the activation energy needed for a reaction to occur, making reaction rates faster. In the case of uncatalyzed reactions, the activation energy is higher, and the reaction rates are slower. Based on our analysis, the most accurate answer is: (D) A different amount of energy is required to reach the transition state of the reaction.