When cellular order increases, what happens to entropy and ATP usage?

• A. Entropy decreases and ATP is produced.
• B. Entropy increases and ATP is produced.
• C. Entropy remains the same and ATP is unchanged.
• D. Entropy decreases and ATP is consumed.

Answer: (D)

When cellular order increases, you’re creating more complex, organized structures, which means a decrease in entropy in that localized system. Building this order requires energy input, so ATP is consumed to drive the anabolic processes that assemble macromolecules and membranes. In other words, making things more ordered costs energy, hence ATP usage goes up and entropy locally goes down. (The overall universe still gains entropy as energy is released as heat during these processes.)