Question 1

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy, speeding up reactions without being consumed.

Question 2

Refer to the graph showing free energy vs. progress of reaction. What does the difference between the two peaks represent?

Accepted Answer

The reduction in activation energy due to the enzyme.

Question 3

Which statement about enzyme specificity is correct?

Accepted Answer

Enzymes have an active site that fits only specific substrates, ensuring reaction specificity.

Question 4

What is the effect of increasing substrate concentration on enzyme activity, as shown in the substrate concentration vs. reaction rate graph?

Accepted Answer

The reaction rate increases until it reaches a maximum velocity ($$V_{max}$$), after which it levels off.

Question 5

A student adds more enzyme to a reaction mixture with excess substrate. What is the expected outcome?

Accepted Answer

The reaction rate will increase as more enzyme is available to catalyze reactions.

Question 6

Which environmental factor can cause an enzyme to denature, resulting in loss of function?

Accepted Answer

High temperature.

Question 7

Why is it important to use a buffer in enzyme experiments?

Accepted Answer

Buffers maintain a constant pH, ensuring optimal enzyme activity.

Question 8

What is the function of a cofactor in enzyme activity?

Accepted Answer

A cofactor binds to the enzyme and activates it, allowing substrate binding.

Question 9

Which of the following best describes competitive inhibition?

Accepted Answer

The inhibitor binds to the active site, preventing substrate binding.

Question 10

A peeled potato turns brown when exposed to air. Which enzyme and substrate are involved in this reaction?

Accepted Answer

Catecholase and catechol.

Question 11

What is the product formed when catechol is oxidized by catecholase in the presence of oxygen?

Accepted Answer

Benzoquinone.

Question 12

Which of the following is true about enzyme inhibitors?

Accepted Answer

Competitive inhibitors bind to the active site and can be overcome by increasing substrate concentration.

Question 13

If an enzyme is placed in an environment with extremely high salt concentration, what is likely to happen?

Accepted Answer

The enzyme will denature due to disruption of ionic bonds.

Question 14

Which equation best represents the change in free energy for a reaction catalyzed by an enzyme?

Accepted Answer

$$\Delta G = G_{products} - G_{reactants}$$

Question 15

Which of the following is an example of a coenzyme?

Accepted Answer

Vitamin B6.

Question 16

In an experiment, the reaction rate of an enzyme-catalyzed reaction is measured at different pH values. What would you expect if the pH is far from the enzyme's optimal range?

Accepted Answer

The reaction rate will decrease.

Question 17

Which of the following best explains the induced fit model of enzyme action?

Accepted Answer

The enzyme changes shape slightly to bind more snugly to the substrate.

Question 18

A lab experiment tests the effect of enzyme concentration on reaction rate. Which variable should be kept constant to ensure valid results?

Accepted Answer

Substrate concentration.

Question 19

Which section of a lab report should include a summary of key findings and their significance?

Accepted Answer

Abstract.

Question 20

In the context of enzyme kinetics, what does $$V_{max}$$ represent?

Accepted Answer

The maximum reaction rate achieved when the enzyme is saturated with substrate.

Enzymes: Structure, Function, and Laboratory Investigation

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