Question 1

Which of the following best describes how enzymes increase the rate of a chemical reaction?

Accepted Answer

By lowering the activation energy required for the reaction

Question 2

A scientist is studying an enzyme-catalyzed reaction. She increases the substrate concentration and observes that the reaction rate increases, but eventually levels off and does not increase further. What is the most likely explanation for this observation?

Accepted Answer

The enzyme is saturated; all active sites are occupied

Question 3

Which of the following is NOT a mechanism by which enzymes lower activation energy ($$E_a$$)?

Accepted Answer

Increasing the overall free energy change ($$\Delta G) of $$the reaction

Question 4

Consider the following reaction: $$A + BC \rightarrow AB + C. In $$the presence of an enzyme, which of the following statements is TRUE?

Accepted Answer

The enzyme lowers the activation energy ($$E_a) $$but does not change $$\Delta G$$

Question 5

A patient has a genetic mutation that alters the shape of an enzyme's active site. Which of the following is the most likely consequence?

Accepted Answer

The enzyme's substrate specificity will decrease, reducing its catalytic activity

Question 6

Which of the following best explains why enzyme activity decreases at temperatures much higher than the enzyme's optimum?

Accepted Answer

The enzyme denatures, losing its specific three-dimensional shape

Question 7

In a laboratory experiment, an enzyme from a bacterium that lives in acidic hot springs is tested at pH 7 and 37°C. What is the most likely outcome?

Accepted Answer

The enzyme will have reduced activity due to non-optimal pH and temperature

Question 8

Which of the following statements about enzyme-substrate binding is correct?

Accepted Answer

Substrate binding occurs at the active site and can induce a conformational change in the enzyme

Question 9

If the pH of a solution containing an enzyme is changed from 7 to 3, what is the most likely effect on enzyme activity?

Accepted Answer

Enzyme activity will decrease because the enzyme's shape and charge properties are altered

Question 10

Which of the following best describes the role of the enzyme in the following energy diagram?

$$	ext{Reactants} ightarrow 	ext{Transition State} ightarrow 	ext{Products}$$

The enzyme:

Accepted Answer

Lowers the activation energy ($$E_a) $$required to reach the transition state

Question 11

A researcher increases the enzyme concentration in a reaction while keeping substrate concentration constant and in excess. What will happen to the rate of product formation?

Accepted Answer

The rate will increase proportionally with enzyme concentration

Question 12

Which of the following is TRUE regarding the fate of an enzyme after it catalyzes a reaction?

Accepted Answer

It is released unchanged and can catalyze another reaction

Question 13

Which of the following scenarios best illustrates the concept of 'induced fit' in enzyme function?

Accepted Answer

The enzyme changes shape slightly when the substrate binds, enhancing catalysis

Question 14

Which of the following factors does NOT affect enzyme activity?

Accepted Answer

The color of the enzyme

Question 15

A metabolic disorder results in the accumulation of a substrate and a lack of product. Which enzyme property is most likely defective?

Accepted Answer

The enzyme cannot bind the substrate due to an altered active site

Question 16

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

The active site has a unique shape and chemical environment that matches only specific substrates

Question 17

Which of the following statements about the effect of pH on enzyme activity is correct?

Accepted Answer

Each enzyme has an optimal pH at which its activity is highest

Question 18

A reaction has a free energy change ($$\Delta G) of$$ $$-10 kJ/$$mol. In the presence of an enzyme, what will be the value of $$\Delta G$$?

Accepted Answer

$$-10 kJ/$$mol

Question 19

Which of the following best describes what happens during the transition state of an enzyme-catalyzed reaction?

Accepted Answer

The substrate is converted into a high-energy, unstable intermediate

Question 20

Which of the following is a real-world example of enzyme specificity?

Accepted Answer

Lactase only catalyzes the hydrolysis of lactose, not sucrose

Week 4 - Sept 26

Study Guide - Practice Questions

Study Guide - Flashcards