Question 1

Which of the following best describes a catabolic pathway in cellular metabolism?

Accepted Answer

A pathway that releases energy by breaking down complex molecules into simpler ones.

Question 2

Which statement correctly applies the first law of thermodynamics to biological systems?

Accepted Answer

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

Question 3

A scientist observes that the breakdown of glucose in cellular respiration releases energy. Which type of metabolic pathway is this, and what is the main purpose?

Accepted Answer

Catabolic pathway; to release energy by breaking down glucose.

Question 4

Which of the following equations correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

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

Question 5

Which scenario best illustrates the second law of thermodynamics in a biological context?

Accepted Answer

A cell uses energy to create order, but some energy is lost as heat, increasing the entropy of the universe.

Question 6

Which of the following is true about spontaneous processes in biological systems?

Accepted Answer

They occur without an input of energy and increase the entropy of the universe.

Question 7

A reaction has $$\Delta G \u003c 0. $$What does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and releases free energy.

Question 8

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

Accepted Answer

Enzymes lower the activation energy, speeding up the rate of reactions.

Question 9

In a metabolic pathway, what would happen if a specific enzyme was missing or nonfunctional?

Accepted Answer

The pathway would stop at the step catalyzed by the missing enzyme, and the product would not be formed.

Question 10

Which of the following statements about free energy is correct?

Accepted Answer

Free energy is the portion of a system's energy that can perform work when temperature and pressure are uniform.

Question 11

A cell synthesizes a protein from amino acids. Which type of metabolic pathway is this, and what is the energy requirement?

Accepted Answer

Anabolic pathway; requires energy input.

Question 12

Which of the following best explains why living organisms must continually obtain energy from their environment?

Accepted Answer

To maintain order and carry out cellular processes, as some energy is always lost as heat.

Question 13

Which of the following is an example of an exergonic reaction in a biological system?

Accepted Answer

The hydrolysis of ATP to ADP and inorganic phosphate.

Question 14

If a system is at equilibrium, which of the following statements is true?

Accepted Answer

The free energy change ($$\Delta G) is $$zero.

Question 15

Which of the following best describes entropy ($$S) in $$the context of biological systems?

Accepted Answer

Entropy is a measure of molecular disorder or randomness.

Question 16

A reaction in a cell has a positive $$\Delta G. $$What does this imply about the reaction?

Accepted Answer

The reaction is non-spontaneous and requires an input of energy.

Question 17

Which of the following is a correct statement about the relationship between free energy and stability?

Accepted Answer

A system with lower free energy is more stable.

Question 18

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

Accepted Answer

Enzymes have active sites with unique shapes that fit only specific substrates.

Question 19

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

Accepted Answer

The synthesis of starch from glucose molecules in plants.

Question 20

A cell is placed in an environment where temperature and pressure are constant. Which of the following determines whether a process can perform work?

Accepted Answer

The free energy change ($$\Delta G) of $$the process.

Metabolism and Thermodynamics in Biology: Study Notes

Study Guide - Practice Questions

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