Question 1

Which of the following best describes the role of enzymes in metabolic pathways?

Accepted Answer

Enzymes act as biological catalysts, lowering the activation energy and speeding up reactions without being consumed.

Question 2

Cellular respiration is an example of which type of metabolic pathway?

Accepted Answer

Catabolic pathway

Question 3

According to the first law of thermodynamics, which statement is correct?

Accepted Answer

Energy can be transferred and transformed, but cannot be created or destroyed.

Question 4

Which chemical equation correctly represents photosynthesis?

Accepted Answer

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 5

What is the primary function of ATP in cellular metabolism?

Accepted Answer

To provide energy for cellular work by transferring phosphate groups.

Question 6

Which process is described as an endergonic reaction?

Accepted Answer

Photosynthesis

Question 7

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 8

Which of the following is an example of feedback inhibition?

Accepted Answer

A product of a metabolic pathway binds to the allosteric site of an enzyme, shutting down the pathway.

Question 9

If an enzyme solution is saturated with substrate, what is the most effective way to increase the rate of product formation?

Accepted Answer

Add more enzyme.

Question 10

Which statement about the second law of thermodynamics is correct?

Accepted Answer

Every energy transfer increases the disorder (entropy) of the universe.

Question 11

Which of the following is true about the specificity of enzymes?

Accepted Answer

Enzymes bind substrates at the active site, which is specific in shape and charge.

Question 12

Which of the following is a correct description of an allosteric inhibitor?

Accepted Answer

It binds to a separate site, stabilizing the inactive form of the enzyme.

Question 13

Which of the following is a real-world example of energy coupling in cells?

Accepted Answer

Using the energy released from ATP hydrolysis to drive the synthesis of glutamine from glutamic acid and ammonia.

Question 14

Which of the following is NOT a way that enzymes lower activation energy?

Accepted Answer

Increasing the temperature of the reaction.

Question 15

Which of the following is an inorganic cofactor required by some enzymes?

Accepted Answer

Zn$$^{2+}$$

Question 16

Why are some bacteria metabolically active in hot springs?

Accepted Answer

Their enzymes have high optimal temperatures.

Question 17

Which of the following best explains why ATP is considered 'spring loaded'?

Accepted Answer

The third phosphate bond in ATP is unstable and releases energy when hydrolyzed.

Question 18

Which of the following would most likely occur if a non-competitive inhibitor is added to an enzyme-catalyzed reaction?

Accepted Answer

The enzyme's shape changes, making the active site nonfunctional.

Question 19

Which of the following equations represents the hydrolysis of ATP?

Accepted Answer

$$ATP + H_2O ightarrow ADP + P_i + 	ext{Energy}$$

Question 20

Which of the following would be the result of adding an allosteric activator to an enzyme?

Accepted Answer

The enzyme's active site is stabilized in its active form, increasing activity.

Energy and Enzymes: Metabolism, Thermodynamics, and Enzyme Function

Study Guide - Practice Questions