Oxidative Phosphorylation Flashcards

Flashcards based on lecture notes about oxidative phosphorylation.

Who is Peter Mitchell?

Proposed the chemiosmotic theory in 1961, describing energy conversion in organisms.

What are the structural features of mitochondria?

Outer mitochondrial membrane, intermembrane space, inner mitochondrial membrane (with cristae), and mitochondrial matrix.

How is the proton gradient established and used?

established by the Etc. The ETC pumps protons from the mitochondrial matrix into the intermembrane space,creating a concentration gradient. This proton gradient drives ATP synthesis as protons flow back into the matrix through ATP synthase.

What happens during Electron Transport System (Chain) reactions?

NADH is oxidized to NAD+ and O2 is reduced to H2O, pumping protons into the intermembrane space.

What are the components of the proton circuit?

ATP synthase (resistor), proton gradient (capacitor), and electron transport system (battery).

What are examples of Electron Transport System Inhibitors?

Rotenone, hydrogen cyanide, carbon monoxide, and antimycin A.

What does oxidative phosphorylation accomplish?

Generates ATP, accounting for 28 out of 32 possible ATP from glucose catabolism.

What is the net reaction of NADH oxidation by the oxidative phosphorylation pathway?

2NADH + 2H+ + 5 ADP + 5 Pi + O2 → 2NAD+ + 5 ATP + 2 H2O

What are the main protein complexes in the electron transport system?

NADH-ubiquinone oxidoreductase (Complex I), Succinate dehydrogenase (Complex II), Ubiquinone-cytochrome c oxidoreductase (Complex III), Cytochrome c oxidase (Complex IV), ATP synthase complex (Complex V)

What happens in Complex I (NADH-ubiquinone oxidoreductase)?

NADH is oxidized while coenzyme Q is reduced; translocates 4 protons.

What happens in Complex II (Succinate dehydrogenase)?

Catalyzes oxidation–reduction of succinate to fumarate; reduces coenzyme Q to QH2.

What happens in Complex III (Ubiquinone-cytochrome c oxidoreductase)?

Reduces cytochrome c, while translocating 4H+.

What is the Q cycle?

Converts 2e– transport process into two 1e– transfers; occurs in complex III.

What happens in Complex IV (Cytochrome c oxidase)?

Cytochrome c is oxidized, while oxygen is reduced to water; 2H+ are translocated across the membrane.

What are the two large structural components of the ATP Synthase Complex?

F1 (catalytic activity) and Fo (proton channel).

What are the components of the ATP Synthase Complex?

Rotor, headpiece, stator.

What transport systems are used in Mitochondria?

ATP/ADP translocase (antiporter) and phosphate translocase.

What does ATP/ADP translocase do?

Exports one ATP for every ADP imported.

What controls aerobic respiration and the citrate cycle?

ADP and ATP, and the ratio of NADH/NAD+.

What happens during chemical uncoupling?

ATP production is reduced, heat is generated.

What characterizes brown adipose tissue?

High levels of UCP1.

Which electron transport system protein complex is also found in the citrate cycle?

Complex II

Where is the Q cycle located?

Complex III

Oligomycin is a complex V inhibitor. If given as an antibiotic, what is the consequence?

Lowered ATP synthesis

Which process is responsible for the most ATP production?

Proton-motive force