When the protein gramicidin is integrated into a membrane, an H channel forms and the membrane becomes very permeable to protons (H ions). If gramicidin is added to an actively respiring muscle cell, how would it affect the rates of electron transport, proton pumping, and ATP synthesis in oxidative phosphorylation?

the rates of proton pumping, electron transport and oxygen uptake will remain the same.

Explanation:the grammicidin causes membranes to become permiable or leaky to protons such that it cannot maintain a proton gradient and this will make ATP synthesis to stop. However, it is crucial to note that the permiability of the membrane has no effect on the ability of electron transport to pump protons, therefore the rates proton pumping, electron transport and oxygen uptake will remain unchanged or thesame.

no effects on ETC, Proton pumping,

but stops ATP synthesis.

Explanation:

The electrochemical gradients set up by the proton motive force(PMF) in the intramembrane of the  mitochondria, ensures constant supply of energy for ATPase synthase to synthesise ATPs. Therefore if proton leakages  occurs,the electrochemical gradient will seize,no energy for ATPase for ATP synthesis, and consequently ATP synthesis is inhibited. Therefore the muscle contraction stops.

In addition  the  Electron Transport Chain(ETC) is regulated by the constant revolve of  Kreb's Cycle,to supply hydrogen by co-factors NADH, FADH2, for chemiosmosis ,so that the hydrogem atoms is  splits  into protons and electrons(for ETC), the leakages of protons at the membrane will have no effects on the ETC.

Furthermore, the PMF for the proton pump will not be affected since the leakage is lesser to the pumping force generated by  PMF pushing the protons across into the intramembrane. Thus the proton pump will not be affected.