Quiz Metabolism and Energy

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

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

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

• 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?

• 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.

• 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.

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?

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

• Growth of the crops must occur spontaneously.

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

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

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

• Photosynthetic organisms produce energy in sugars from sunlight.

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

• Living organisms must increase the entropy of their surroundings.

• 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.

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

• The first law of thermodynamics is being violated

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

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

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

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

• ΔH is positive

• ΔH is negative

• ΔS is negative

• ΔG is negative

An exergonic (spontaneous) reaction is a chemical reaction that

• leads to a decrease in the entropy of the universe

• is common in anabolic pathways

• occurs only when an enzyme or other catalyst is present

• releases energy when proceeding in the forward direction

Which of the following reactions would be endergonic?

• glucose + fructose → sucrose

• C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O

• HCl → H⁺ + Cl^-

• ATP → ADP + P_i

Metabolic pathways in cells are typically far from equilibrium. Which of the following processes tend(s) to keep these pathways away from equilibrium?

• the continuous removal of the products of a pathway to be used in other reactions

• The first and second listed responses are correct.

• an input of free energy from outside the pathway

• The first, second, and third listed responses are correct.