Oxidative Phosphorylation

Flashcards about oxidative phosphorylation.

What are the two mechanisms for ATP synthesis?

Substrate level phosphorylation and oxidative phosphorylation

What is substrate level phosphorylation? (+ example)

The transfer of phosphate moieties from a donor to an acceptor. Pyruvate kinase in glycolysis catalyzes the transfer of a phosphate group from phosphoenolpyruvate to ADP, forming ATP.

What reducing equivalents are used to store energy in oxidative phosphorylation?

NADH and FADH2

What creates the electrochemical gradient in oxidative phosphorylation?

Proton pumps transporting H+ from the matrix to the intermembrane space

What is another name for ATP synthase?

Complex V

Approximately what is the pH of the mitochondrial matrix?

7.8

Approximately what is the pH of the intermembrane space of the mitochondria?

7.0-7.4

What are the two major portions of the ATP synthase?

F0 and F1

Which subunits form a ring-like structure embedded in the inner mitochondrial membrane?

c subunits

What is the F1 portion of the ATP synthase also known as?

Head piece

Which subunits are homologous in the ATP synthase?

α and β subunits

What part of the ATP synthase rotates as the proton gradient is discharged?

c-ring and the γ subunit

What happens to the aspartic acid residue when a proton crosses the channel?

It becomes protonated

What is UCP1?

A transmembrane protein in brown adipose tissue that acts as a proton channel.

What is the function of citrate in the Krebs cycle?

It acts as a negative regulator of citrate synthase activity (negative feedback loop).

What is the MERRF syndrome caused by?

A maternally-inherited mutation at position 8344 in the mitochondrial genome, disrupting the mitochondrial gene for tRNA-Lys.

What are some of the major symptoms of MERRF?

Progressive myoclonic epilepsy, ragged red fibers, short stature, hearing loss, lactic acidosis, exercise intolerance, poor night vision.

What is a radical?

An atom, molecule, or ion with unpaired valence electron(s) that is likely to take part in chemical reactions.

What is the Fenton reaction?

The reaction where hydrogen peroxide reacts with iron to form a hydroxyl radical.