Question

The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on?

Answer 1

It will be on the cytoplasmic side of the endoplasmic reticulum

Step-by-step explanation:

The inner mitochondria protein called Adenine Nucleotide Translocator or ADP/ATP carrier protein, maintains the transport of ADP into the matrix of the mitochondria from the cytoplasm for ADP to be available for ATPase synthesis of ATP, from ADP and Pi(inorganic phosphate ion) during chemiosmosis of oxidative phosphorylation in the mitochondria.

The same carrier proetin also convey the synthesized ATPs back to the Cytoplasm for cellular utilization.

Therefore the ATP binding site should at the cytoplasmic side of the E.R, because the cytoplasm of the E.R is the site of deposits of synthesized ATP s, thus proximity of the ATP-binding site to it is needed.