Question

Inhibitors of Oxidative Phosphorylation The following chemicals inhibit oxidative phosphorylation: Cyanide: Cyanide is a naturally occurring compound that binds to protein complex IV of the mitochondrial electron transport chain and prevents transfer of electrons from the protein. Metformin: At the cellular level, chemically synthesized metformin, a drug commonly prescribed for Type 2 diabetes, inhibits mitochondrial respiration by blocking complex I. Dinitrophenol: Dinitrophenol is a metabolic poison that can be sold legally as a pesticide. Although it is lethal to humans, it is also sold as an unregulated weight-loss product. This molecule can bind to H+ ions and then, because the molecule is nonpolar, it diffuses across cell membranes. oligomycin: This is an antibiotic that inhibits ATP synthase by blocking its proton channel. The proton channel is necessary for oxidative phosphorylation of ADP to ATP.

Answer 1

1. The figure below shows the essential components of oxidative phosphorylation in mitochondria. Label the following: a. The intermembrane space and the mitochondrial matrix b. Location where cyanide, dinitrophenol and oligomycin bind Oligomycin binding C. The direction protons are pumped site Cynide binding site Lower pH Intermembrane space II Matrix H ATP synthase Higher pH Dinitropheno! Direction of proton pump