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

• A. All types of cellular respiration produce ATP.
• B. Cellular respiration releases some energy as heat.
• C. The first and second choices are correct.
• D. The first, second, and third choices are correct.
• E. The aerobic respiration of one molecule of glucose produces six molecules each of carbon dioxide and water.

Answer: (E)

Verified step by step guidance

1. Understand the second law of thermodynamics: It states that in any energy transfer or transformation, the total entropy (disorder) of a system and its surroundings always increases.
2. Apply this concept to biological reactions: In biological systems, energy transformations are not 100% efficient, and some energy is always lost as heat, increasing the entropy of the surroundings.
3. Analyze the options: The first option states that cellular respiration produces ATP, which is an energy transformation but does not directly address entropy or energy loss.
4. Consider the second option: Cellular respiration releases some energy as heat, which aligns with the second law of thermodynamics as it indicates an increase in entropy.
5. Evaluate the correct answer: The aerobic respiration of glucose producing carbon dioxide and water involves breaking down a complex molecule into simpler ones, increasing entropy, and releasing energy as heat, which is consistent with the second law of thermodynamics.