Evaluate the role of antiporters in the malate-aspartate shuttle cycle.

• A. Antiporters convert oxaloacetate to aspartate without energy cost.
• B. Antiporters enhance ATP yield by increasing electron transport efficiency.
• C. Antiporters directly transport NADH into the mitochondrial matrix.
• D. Antiporters facilitate the exchange of malate and alpha-ketoglutarate, maintaining the shuttle cycle.

Answer: (D)