[Campbell Biology P.199] Figure 8.8b illustrates a multistep open hydroelectric system, whic... | Practice Question

Figure 8.8b illustrates a multistep open hydroelectric system, which is analogous to cellular respiration. Which statement best explains how this system and cellular respiration avoids reaching equilibrium?

  • A: Waste products are rapidly expelled, preventing their accumulation and reversal of reactions.
  • B: Each reaction's product serves as a reactant for the subsequent reaction, preventing product accumulation.
  • C: The system operates in a closed environment, allowing reactants to be continuously recycled.
  • D: The free energy difference between the initial reactants and final products is minimal, promoting constant forward movement.

Explanation

The key to maintaining the non-equilibrium state in a multistep pathway, like cellular respiration, is that the product of one reaction immediately becomes the reactant for the next. This continuous consumption of products prevents them from accumulating and thus prevents the reactions from reaching equilibrium.