Introduction to Metabolism

Which of the following correctly states the relationship between anabolic and catabolic pathways?

• Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.

• Degradation of organic molecules by anabolic pathways provides the energy to drive catabolic pathways.

• Catabolic pathways produce usable cellular energy by synthesizing more complex organic molecules.

• Energy derived from catabolic pathways is used to drive the breakdown of organic molecules in anabolic pathways.

• The flow of energy between catabolic and anabolic pathways is reversible.

Organisms are described as thermodynamically open systems. Which of the following statements is consistent with this description?

• Because energy must be conserved, organisms constantly recycle energy and thus need no input of energy.

• The metabolism of an organism is isolated from its surroundings.

• Heat produced by the organism is conserved in the organism and not lost to the environment.

• Organisms acquire energy from and lose energy to their surroundings.

• All of the listed responses are correct.

Consider the growth of a farmer's crop over a season. Which of the following correctly states a limitation imposed by the first or second law of thermodynamics

• To obey the first law, the crops must represent an open system.

• The process of photosynthesis produces energy that the plant uses to grow.

• The entropy of the universe must decrease to account for the increased entropy associated with plant growth.

• Growth of the crops must occur spontaneously.

• All of the listed responses are correct.

Which of the following states the relevance of the first law of thermodynamics to biology?

• Living organisms must increase the entropy of their surroundings.

• Energy is destroyed as glucose is broken down during cellular respiration.

• Photosynthetic organisms produce energy in sugars from sunlight.

• Because living things consume energy, the total energy of the universe is constantly decreasing.

• Energy can be freely transformed among different forms as long as the total energy is conserved.

Which of the following is an example of the second law of thermodynamics as it applies to biological reactions?

• The aerobic respiration of one molecule of glucose produces six molecules each of carbon dioxide and water.

• All types of cellular respiration produce ATP.

• Cellular respiration releases some energy as heat.

• The first and second choices are correct.

• The first, second, and third choices are correct.

According to the second law of thermodynamics, which of the following is true?

• Energy conversions increase the order in the universe.

• The total amount of energy in the universe is constant.

• All reactions produce some heat.

• The decrease in entropy associated with life must be compensated for by increased entropy in the environment in which life exists.

• The entropy of the universe is constantly decreasing.

If the entropy of a living organism is decreasing, which of the following is most likely to be occurring simultaneously?

• Energy input into the organism must be occurring to drive the decrease in entropy.

• Heat is being used by the organism as a source of energy.

• The first law of thermodynamics is being violated.

• In this situation, the second law of thermodynamics must not apply.

• The entropy of the organism's environment must also be decreasing.

Which part of the equation ΔG = ΔH – TΔS tells you if a process is spontaneous?

• ΔG

• TΔS

• ΔS

• All of these values reveal the direction in which a reaction will go.

• ΔH

If, during a process, the system becomes more ordered, then __________.

• ΔG is negative

• ΔG is positive

• ΔH is negative

• ΔS is negative

• ΔH is positive

When one molecule is broken down into six component molecules, which of the following will always be true?

• ΔS is negative.

• ΔG is positive.

• ΔH is negative.

• An input of free energy is needed.

• ΔS is positive.