When the antibiotic valinomycin is added to actively respiring mitchondria, several things happen: the yield of ATP decreases, the rate of O2 consumption increases, heat is released, and the proton gradient across the inner mitochondrial membrane decreases. What type of inhibitor is valinomycin?

The correct answer will be - Uncoupler (ionophore)

Explanation:

Valinomycin is a antibiotic which uncouples the process of ATP synthesis and the electron transport chain.

The valinomycin decreases the yield of ATP synthesis by allowing the inward movement of the K⁺ ions across the inner mitochondrial membrane. This inward movement disrupts the proton gradient which decreases the yield of the ATP synthesis.

Also, the consumption of oxygen increases in the electron transport chain which generates heat during ATP synthesis.

Thus, Uncoupler (ionophore) is the correct answer.