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, ii, and iii
b. ii and iii only
c. i and ii only
d. i only

Explanation:

• For Statement I: According to kinetic molecular theory, increasing temperature gives molecules more kinetic energy, so substrates move faster at higher temperatures. This is true.
• For Statement II: Faster - moving substrates have more frequent collisions with enzymes. Up to the optimal temperature, this increased collision frequency leads to a higher reaction rate. This is true.
• For Statement III: Enzymes have an optimal temperature. Beyond the optimal temperature, enzymes (which are proteins) can denature, and the reaction rate will decrease instead of always increasing with higher temperature. So this statement is false.

Since Statements I and II are true and Statement III is false, the correct option is C.

Answer:

C. I and II only