lecture 20

i fucking hate this class

What is the primary source of high energy electrons?

NADH and FADH2 are produced in TCA

What complex does NADH donate to?

Complex I

What complex does FADH2 donate to?

Complex II

High E0 means what?

More positive → stronger oxidizing agent

• higher tendency to accept electrons

Low E0 means what?

More negative → stronger reducing agent

• higher tendency to donate electrons

What is redox potential?

A molecules tendency to donate and accept electrons in a redox reaction

How are changes in reduction potential and free energy related?

The equation Delta G = -nFE

• n = number of electrons transferred

• F = Faraday constant

• E = Redox potential

What are the four complexes that are found in the ETC?

• Complex I: NADH-Q Oxidoreductase

• Complex II: Succinate-Q Reductase

• Complex III: Q-Cytochrome c Oxidoreductase

• Complex IV: Cytochrome c oxidase

What do the complexes do?

Pump protons out of the mitochondrion, creating the proton gradient

Which complexes pump protons from the matrix to the intermembrane space?

Complex I, III, IV

How does NADH differ from FADH2?

Donates electrons to complex I

• Flow through I → III → IV

• Pumps a total of 10 protons into the intermembrane space

How does FADH2 differ from NADH

Donates electrons to Complex II

• Electrons flow through II→ III→IV

• Since Complex II does not pump protons, FADH2 only contributes pumping of 6 protons

• NADH generates more ATP because of this difference

What does Flavin mononucleotide (FMN) do?

Accepts electrons from NADH in complex I

What does Iron sulfur (Fe-S) clusters do?

Undergo oxidization reduction reactions, complex I, II, III

What do hemo groups do?

Found in complexes III and IV, transfer electrons via Fe2+ and Fe3+ states

What does coenzyme Q do?

Transfers electrons between complex I and II → Complex III

What does cytochrome c do?

Transfers electrons from complex III → IV

What does superoxide dismutase?

Converts superoxide radicals into hydrogen peroxide

What does Catalase do?

Converts hydrogen peroxide into H2O and water to prevent further damage?