Question

Very low concentrations of detergent make membranes leaky to small molecules and ions without damaging proteins. In isolated mitochondria exposed to detergent, the molecules of the electron transport chain and of ATP synthase remain intact. Do you expect ATP synthesis to continue in the presence of low concentrations of detergent

Answer 1

Options

A. Yes, because all enzymes and electron carriers are functional

B. No, because with a leaky membrane, the proton gradient cannot be maintained

C. No, because leaky membranes inhibit glycolysis

D. No, because leaky membranes do not allow NADH and FADH2 to donate their electrons to the electron transport chain

Answer:

B. No, because with a leaky membrane, the proton gradient cannot be maintained

Explanation:

The proton motive force (PMF) provides the needed pump  to generate electrochemical gradients of proton needed for continue influx  into the matix of the mitochondria. The proton Influx generates the energy needed by  protein ATPase Synthase for  synthesis  of ATPs by adding inorganic phosphate to ADP to give ATP.

               ADP + Pi -----------→ ATP.

If the mitochondria;l  intramembrane leaks, then the PMF can  not be sustained, therefore electtrochermical gradient which supplies the energy for ATP synthase for ATP synthesis will not be available. Therefore ATP synthesis stops.