The adenine nucleotide translocase (ANT, also called ADP/ATP translocase) exchanges ATP and ADP across the inner mitochondrial membrane. Which statement about this transporter is correct?
- A It exchanges ATP4- out of the matrix for ADP3- in, is electrogenic, and is inhibited by atractyloside ✓
- B It is an antiporter that exchanges 2 ADP3- into the matrix for 2 ATP4- out, electroneutrally
- C It transports ATP into the matrix in exchange for ADP out and is activated by oligomycin
- D It transports ATP and ADP in a 1:1 ratio but requires a proton gradient to function
Correct answer: A. It exchanges ATP4- out of the matrix for ADP3- in, is electrogenic, and is inhibited by atractyloside
Explanation
ANT exchanges one ATP4- (out) for one ADP3- (in), moving net negative charge out of the matrix. This electrogenic exchange is driven by the membrane potential (matrix negative). Atractyloside blocks the cytosolic face; bongkrekic acid blocks the matrix face. Distractor B is wrong because the stoichiometry is 1:1 and it is electrogenic, not electroneutral. Distractor C is wrong because ATP exits, not enters.
Reference: Lehninger Principles of Biochemistry, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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