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question 8
enzymes speed up a chemical reaction by ____.
a. increasing the energy in the system
b. lowering the activation energy
c. lowering the optimal ph
d. increasing the reaction temperature
e. increasing the activation energy

Explanation:

Enzymes are biological catalysts. Catalysts work by lowering the activation energy of a reaction. Activation energy is the minimum energy required for a reaction to occur. By reducing this energy barrier, more reactant molecules have sufficient energy to overcome it and form products, thus speeding up the reaction.

• Option a: Increasing the energy in the system is not how enzymes work. Enzymes do not add energy to the system in this way.
• Option c: Lowering the optimal pH is not the mechanism for speeding up reactions. Optimal pH is related to the enzyme's stability and activity conditions, not the reaction - speeding mechanism.
• Option d: Enzymes are not about increasing reaction temperature. They function at relatively mild temperatures (compared to non - biological catalysts in some industrial processes).
• Option e: Increasing activation energy would slow down the reaction, which is the opposite of what enzymes do.

Answer:

B. lowering the activation energy