Oxidative Phosphorylation P2

What is the primary function of NADH in ATP formation?

NADH oxidation is highly exergonic, releasing a large amount of energy that powers ATP synthesis.

How does PMF contribute to ATP synthesis?

PMF drives ATP synthesis by powering ATP synthase.

What type of gradient is created by the oxidation of NADH and FADH2?

A proton gradient across the inner mitochondrial membrane.

What are the components of the ATP synthase F1 subunit?

The F1 subunit is composed of α₃β₃γδε.

What is the role of the γ subunit in ATP synthase?

The γ subunit connects to F0 and breaks symmetry.

How many protons are pumped by Complex I during electron transport?

Complex I pumps 4 H⁺.

What is the function of ATP-ADP translocase?

To exchange cytoplasmic ADP for mitochondrial ATP.

What effect does no availability of ADP have on the electron transport chain (ETC)?

No ADP means no electron flow through the ETC.

What is the main purpose of the chemiosmotic theory?

To explain how ATP synthesis requires an electrochemical proton gradient.

What does a full 360° rotation of the ATP synthase yield?

Three ATP molecules.

What is the significance of the proton flow mechanism in ATP synthesis?

It powers the rotation of the c-ring, which drives ATP release.

How does uncoupling occur in oxidative phosphorylation?

When protons bypass ATP synthase, as seen with compounds like 2,4-dinitrophenol.

What type of transport does the phosphate carrier perform?

Exchanges H₂PO₄⁻ for OH⁻.

What is the role of UCP-1 in mitochondria?

Causes nonshivering thermogenesis in brown adipose tissue.

How many c-subunits are found in yeast ATP synthase?

Ten c-subunits.

What happens to cytochrome c during apoptosis?

It is released upon outer membrane permeabilization, activating caspase cascade.

What is respiratory control related to in oxidative phosphorylation?

ADP availability controls the electron transport chain.

What inhibits ATP synthase in certain conditions?

IF1 inhibits ATP synthase hydrolysis mode when O₂ is limited.

What is the relationship between ATP yield and c-subunits in humans?

In humans, there are eight c-subunits, resulting in ~2.7 H+ per ATP.

What does a loose conformation (L) allow for in ATP synthase?

ADP and inorganic phosphate (Pi) are held in place.

What does proton flow through the F0's a subunit achieve?

It neutralizes aspartate in c-subunits, driving the rotation of the c-ring.

What is the impact of Complex III on proton pumping?

Complex III pumps 2 H⁺.

What does the term 'binding-change mechanism' refer to?

The cycles of conformational changes in β subunits driving ATP synthesis.

What is the output when oxidative phosphorylation operates optimally?

Approximately 30 ATP per glucose.

What is the consequence of Complex I dysfunction in mitochondrial diseases?

It results in decreased ATP production and increased reactive oxygen species (ROS).

What are the consequences of mitochondrial membrane integrity according to the chemiosmotic theory?

An intact inner membrane and its impermeability to ions are required for ATP synthesis.

What does the experimental evidence of PMF support?

The PMF model in ATP synthesis.

How does the body's thermogenic response to cold exposures involve UCP-1?

UCP-1 activation leads to heat generation through nonshivering thermogenesis.

What are the inhibitors belonging to the oxidative phosphorylation pathway?

Rotenone, amytal, antimycin A, cyanide, azide, and CO.

What role do Brown adipose tissue's UCPs play beyond thermogenesis?

They are involved in energy regulation and may affect body weight.