What are the 2 separate processes of oxidative phosphorylation?

- Oxidation of reduced cofactors and reduction of O2 - Phosphorylation of ADP to ATP

How are the two processes of OP linked?

Through p+ gradient across mitochondrial membrane

What cofactors are reversibly oxidized/reduced during e- transport? Which are prosthetic groups and lipid-soluble cofactors? 5

Prosthetic groups: FMN, Iron-sulfur clusters, Cu, Cytochrome heme groups Lipid-soluble cofactor: Coenzyme Q

E- move from cofactors w/ _____ reduction potential to those w/ ________ reduction potentials

Lower to Higher

What is the rxn of FMN

FMN + 2H + 2e- -> FMNH2

What is the rxn of iron-sulfur cluster?

Fe3+ + e- -> Fe2+

Cytochromes are __________ that carry out e- transport

Hemoproteins

T/F: Cytochromes switch between oxidized as reduced states

True

What is the purpose of coenzyme Q? What is the rxn?

- Transport e- to complex III from complexes I and II and innter mito membrane (the cosubstrate for the complexes) - Q (ubiquinone) + 2H + 2e- -> QH2

What is reductional potential?

Affinity for e-

What does higher reduction potential mean for delta G?

More negative delta G

E- move from compounds w/ _________ reduction potential to ______ reduction potential

Lower to higher

Free energy changes from redox rxn can be used to _________ across the _______, what kind of transport is this?

- Transport protons - Membrane - Primary active T

Every NADH reoxidized results in ___ p+ being moved ____ matrix

- 10p+ - Moved out of matrix

What is the terminal e- acceptor? Why?

Oxygen - High reduction potential

What does e- transport do physically to the complexes?

Cause conformational change = can pump H+ ions

What is complex II?

Succinate dehydrogenase

What prosthetic group does complex II have?

FAD

What is the purpose of succinate dehydrogenase?

- Catalyze oxidation of succinate to fumarate as part of citric acid cycle

Where do the e- from succinate go?

Transferred to coenzyme Q in membrane

T/F: p+ are not moved across membrane at complex II

False, they are

Every FADH2 reoxidized results in __ p+ being moved __ matrix

- 6 p+ - Moved out of matrix

What is the potential energy of the H+ gradient converted to?

Chemical energy in the PA bonds of ATP

How many H+ are needed per ATP synthesized by ATP synthase?

3H+

What are the 2 portions of ATP synthase?

Fo: - Transmembrane portion - P+ pass through - Triggers conformational change in F1 F1: - Catalytic portion - Synthesis of ATP from ADP and Pi

What determines p+ movement and O2 consumption?

Rate of ATP synthesis

Every turn of the central shaft of ATP synthase is associated w/ what? Why?

Generation of 3 ATP - 3 active sites make 1 ATP

Where does newly synthesized ATP go? Why?

From mitochondrial matrix into cytosol to drive energy-requiring processes

Where does the ADP and Pi produced in the cytosol go?

Back to mito matrix

What is the P:O ratio?

Amount of ATP (P) per oxygen (O) atom reduced to water

What is the P:O ratio for NADH reoxidized?

2.5

What is the P:O ratio for FADH2 reoxidized?

1.5

The rate of OP is determined by the conc of _____

ADP

O2 consumption ____ when ADP conc rises

Increase

Oxygen _____ increases in isolated mitochondira when ATP synthesis is stimulated (Addn of ADP_

Consumption

Uncoupled systems allow p+ to enter the matrix w/o ________, what is a separate product that may occur?

ATP synthesis - Generate heat instead of ATP

Oxygen consumption _________ in the presence of an uncoupler

Increases - e- transport occurs w/o ATP synthesis

What happens in the presence of an uncoupler?

- P+ gradient dissipated faster - Rate of e- transport increases - Rate of reoxidation of reduced e- carriers increases - Rate of rxn in citric acid cycle increases