Question

When the antibiotic valinomycin is added to actively respiring mitochondria, several things happen: the yield of atp decreases, the rate of o2 consumption increases, heat is released, and the ph gradient across the inner mitochondrial membrane increases. explain these observations by listing the causal order of events that occur beginning with the addition of valinomycin to the respiring mitochondria and ending with the release of heat?

Answer 1

Valinomycin  is an Ionophores- i.e it makes the inner membrane permeable to compounds which are ordinarily unable to cross.

The amphipathic molecules dissolve in phospholipid bilayers of the mitochondria

It shields the electric charge as the ion passes through the membrane, providing a polar environment for the ion and a hydrophobic face to the other side. mobile carrier catalyzes the electrical movement of K+ across phospholipid bilayers. Hence Accumulation of potassium inside the mitochondria

This dissipates the essential transmembrane electrochemical gradients causing tremendous metabolic upheaval in the mitochondria.