Question 1

Which of the following best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

Energy can be transferred or transformed, but never created or destroyed.

Question 2

A roller coaster at the top of a hill is an example of which type of energy, and why?

Accepted Answer

Potential energy, because of its position above the ground.

Question 3

Which equation correctly relates the change in free energy ($$\Delta G) to $$enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T$$)?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 4

Which of the following statements about exergonic reactions is TRUE?

Accepted Answer

They occur spontaneously and release free energy.

Question 5

A campfire releases heat and light as wood burns. Which law of thermodynamics does this illustrate, and why?

Accepted Answer

Second law, because energy is transformed and entropy increases.

Question 6

Which of the following best explains why cells never reach metabolic equilibrium?

Accepted Answer

Cells constantly allow materials to flow in and out, preventing equilibrium.

Question 7

Which of the following is an example of energy coupling in cells?

Accepted Answer

Using the energy released from ATP hydrolysis to drive the synthesis of a protein.

Question 8

Which of the following statements about ATP is FALSE?

Accepted Answer

The energy released from ATP comes directly from breaking phosphate bonds.

Question 9

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

Accepted Answer

Enzymes speed up reactions by lowering the activation energy barrier.

Question 10

A competitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Competing with the substrate for binding at the active site.

Question 11

Which of the following is a correct statement about feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway acts as an allosteric inhibitor of an enzyme early in the pathway.

Question 12

Which of the following best explains why organizing a messy room requires energy, while disorder happens spontaneously?

Accepted Answer

The second law of thermodynamics states that entropy (disorder) tends to increase unless energy is used to maintain order.

Question 13

Which of the following is TRUE about the effect of temperature on enzyme activity?

Accepted Answer

Each enzyme has an optimal temperature at which its activity is highest.

Question 14

Which of the following is an example of an anabolic pathway?

Accepted Answer

The synthesis of protein from amino acids.

Question 15

Which of the following statements about cofactors is CORRECT?

Accepted Answer

Cofactors can be either inorganic ions or organic molecules called coenzymes.

Question 16

A reaction has $$\Delta G = +30 kJ/$$mol. Which of the following is TRUE?

Accepted Answer

The reaction is endergonic and requires an input of energy.

Question 17

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

Accepted Answer

Changing the $$\Delta G of $$the reaction.

Question 18

Which of the following best describes allosteric regulation of an enzyme?

Accepted Answer

A regulatory molecule binds to a site other than the active site, changing the enzyme's activity.

Question 19

Which of the following is TRUE about the relationship between free energy and stability in a system?

Accepted Answer

Systems with lower free energy are more stable.

Question 20

Which of the following is a real-life example of a noncompetitive inhibitor?

Accepted Answer

A toxin that binds to a site other than the active site, changing the enzyme's shape and function.

Chapter 8: An Introduction to Metabolism – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards