The Electron Transport Chain: Complexes I and II

The video tutorial explains the roles of complexes one and two in the mitochondrial respiratory chain. Complex one, known as NADH dehydrogenase, oxidizes NADH to NAD, transferring electrons to coenzyme Q, and pumps protons into the inner membrane space. Complex two, or succinate dehydrogenase, is part of the TCA cycle and transfers electrons from succinate to FAD, forming FADH2, which then reduces coenzyme Q. Both complexes contribute to the ubiquinol pool, which is processed by complex three.

What is the primary function of complexes one and two in the mitochondrial respiratory chain?

• To synthesize proteins

• To oxidize glucose

• To contribute to the ubiquinol pool

• To generate ATP directly

Which enzyme is responsible for oxidizing NADH in complex one?

• Succinate dehydrogenase

• Cytochrome c oxidase

• ATP synthase

• NADH dehydrogenase

What is the role of FMN in complex one?

• It synthesizes ATP

• It acts as a proton pump

• It transfers electrons from NADH

• It oxidizes succinate

Which cycle is succinate dehydrogenase a part of?

• Urea cycle

• TCA cycle

• Calvin cycle

• Glycolysis

What is the main reaction catalyzed by succinate dehydrogenase?

• Reduction of oxygen to water

• Synthesis of ATP from ADP

• Oxidation of NADH to NAD

• Oxidation of succinate to fumarate

Which complex does not pump protons in the mitochondrial respiratory chain?

• Complex two

• Complex one

• Complex four

• Complex three

What is the common product of complexes one and two that is used by complex three?

• ATP

• NADH

• FADH2

• Ubiquinol