MCQ – 21247

Correct Answer » D Explanation

ATP is transported across the inner mitochondrial membrane by a specific carrier protein called Adenine Nucleotide Translocase (ANT).
This transporter exchanges ATP produced inside the mitochondria with ADP from the cytosol. This exchange is essential for cellular energy metabolism.

Explanation of Why Other Options Are Incorrect

Option A: NADH
NADH cannot directly cross the inner mitochondrial membrane.
Instead, its electrons are transferred via shuttle systems such as the malate-aspartate shuttle and glycerol-3-phosphate shuttle.

Option B: Acetyl-CoA
Acetyl-CoA cannot cross the mitochondrial membrane directly.
It is transported indirectly in the form of citrate via the citrate shuttle.

Option C: NADPH
NADPH is mainly used in cytosolic anabolic reactions such as fatty acid synthesis.
It does not require transport across the mitochondrial membrane and has no specific transporter there.