(a) Valinomycin, an antibiotic ionophore, allows the free passage of only K+ ions across a membrane. If K+ and valinomycin are added to respiring, fully coupled ATP-synthesizing mitochondria, what happens to the pH gradient and the ΔΨ?
(b) Nigericin, another ionophore, exchanges one K+ for one H+. How does this affect ATP synthesis and electron transport in mitochondria?
(c) Gramicidin allows the free passage of many small molecules and ions across the membrane. What happens to ATP production and electron transport in the presence of gramicidin?