Question

mini-quiz: temperature and enzymes
based off of your observations, which of the following statements would be true?
i. substrates (molecules) move faster at higher temperatures.
ii. faster moving substrates collide with the enzyme more, causing the reaction rate to increase until the optimal temperature is reached.
iii. hotter temperatures always result in faster reaction rates.
a. i and ii only
b. ii and iii only
c. i only
d. i, ii, and iii

Explanation:

• Statement I: According to the kinetic - molecular theory, as temperature increases, the kinetic energy of molecules (substrates in this case) increases, so they move faster.
• Statement II: When substrates move faster, they have a higher probability of colliding with the enzyme. Before the optimal temperature, these increased collisions lead to an increase in the reaction rate.
• Statement III: After the optimal temperature, the enzyme (which is usually a protein) can denature. Denatured enzymes lose their functional shape, and the reaction rate decreases. So, hotter temperatures do not always result in faster reaction rates.

Answer:

A. I and II only