Question 15 of 20 The adenine nucleotide translocase ( ADP – ATP translocase), a transporter located in the inner mitochondrial membrane, transports ADP and ATP across the membrane. It is an antiporter. (Recall that these adenine nucleotides are negatively charged: ADP 3 − and ATP 4 .) Phosphate translocase is also located in the inner mitochondrial membrane. It transports H + and phosphate ( H 2 PO − 4 ) across the membrane. It is a symporter. Which direction is ATP 4 − transported during times of active oxidative phosphorylation? into the mitochondrial matrix there is no net flow of ATP 4 − out of the mitochondrial matrix What drives the transport of adenine nucleotides? the electrochemical gradient (membrane potential) transport is coupled with ATP hydrolysis simple diffusion What is the ratio of ADP to ATP transported by the adenine nucleotide translocase? That is, how many ADP are transported for each ATP transported? 4 ADP : 3 ATP 3 ADP : 4 ATP 2 ADP : 3 ATP 1 ADP : 1 ATP What drives the transport of H 2 PO − 4 across the membrane? Which direction is it transported during oxidative phosphorylation? H 2 PO − 4 is transported into the matrix in a process driven by ATP hydrolysis. H 2 PO − 4 is transported out of the matrix in a process driven by the electrochemical gradient. H + and H 2 PO − 4 are transported into the matrix in a process driven by the proton gradient. H 2 PO − 4 is transported out of the matrix as H + enters through ATP synthase.