Electron transport chain Transitional Reasoning Download PDF

Questions

1. 1.

   Isolated, functioning mitochondria are supplied with pyruvate, inorganic phosphate, and ADP in an oxygenated buffer, establishing steady ATP production. Researchers then introduce an ionophore that selectively allows protons to diffuse freely across the inner mitochondrial membrane down their concentration gradient. Based on the mechanism of oxidative phosphorylation, which change will occur immediately following the introduction of this substance?

   • A) Both oxygen consumption and ATP synthesis will cease entirely due to feedback inhibition of Complex I.
   • B) ATP synthesis will increase to compensate for the accelerated reduction of oxygen to water.
   • C) Electron transport will halt because the transfer of electrons from NADH becomes thermodynamically unfavorable.
   • D) Oxygen consumption will continue or increase while ATP synthesis declines sharply.