Q10. Which of the following would be the same in either an enzyme-catalyzed or a noncatalyzed reaction?

Background

Topic: Enzyme Catalysis & Reaction Energy Diagrams

This question tests your understanding of how enzymes affect chemical reactions, specifically regarding the energy changes and reaction progress. The diagram shows the free energy changes during a reaction, with and without an enzyme.

Key Terms and Concepts:

• Activation Energy (): The energy barrier that must be overcome for reactants to become products.

• Free Energy (): The difference in energy between reactants and products; determines whether a reaction is spontaneous.

• Enzyme: A biological catalyst that speeds up reactions by lowering the activation energy, but does not change the overall free energy change ().

• Energy Diagram: Visual representation of energy changes during a reaction, showing reactants, products, and the transition state.

Step-by-Step Guidance

1. Examine the energy diagram. Notice the two curves: one for the uncatalyzed reaction (higher peak) and one for the enzyme-catalyzed reaction (lower peak).

2. Identify what each labeled arrow (a, b, c, d, e) represents. Typically, these arrows show activation energy, free energy change, and other energy differences.

3. Recall that enzymes lower the activation energy (the height of the peak), but do not change the starting or ending energy levels of reactants and products.

4. Determine which energy value would remain unchanged whether or not an enzyme is present. Focus on the difference between the energy of reactants and products.

5. Set up your answer by matching the correct arrow to the concept that is unchanged in both catalyzed and uncatalyzed reactions.

Try solving on your own before revealing the answer!