Oxidative phosphorlyation and Metabolic poisons

Question 1

Cyanide

Answer 1

cytochrome oxidase

Question 2

carbon monoxide

Answer 2

Fe2+ and haem

Question 3

malonate

Answer 3

competitive succinate dehydrogenase inhibitor

Question 4

Rotenone

Answer 4

transfer from complex I to complex Q

Question 5

Oligomycin

Answer 5

inhibits ETC electron flow because H+ build up until saturated

ATP synthase inhibitor

Question 6

Dinitrophenol

Answer 6

Uncoupling reaction

Question 7

What is the chemiosmotic model

Answer 7

1. protons translocated (moved) from matrix to inter-membranal space
2. allowed back into matrix down gradient by channel coupled to ATP synthase, generating ATP

Question 8

Summarise the electron transport chain

Answer 8

Enzymes accept electrons and in doing so a proton from the aq matrix solution, and as electrons pass through the complexes the proton is pumped to the intermembrane space

NADH dehydrogenase complex has a higher affinity for electrons than NADH so removes them to regenerate NAD+

Each complex of chain has higher affinity for electrons than previous, ensuring unidirectional movement of electrons, losing energy at each step. When four electrons arrive at the cytochrome oxidase complex, a reaction with molecular oxygen and 4 H+ forms two molecules of water.

Question 9

What is the structure of ATP synthase

Answer 9

membrane bound part (F0) and projection into matrix (F1).

1. When H+ flow through F0, rotation of F1 drives transition states and alters ATP and ADP affinity
2. Conformational energy flows from catalytic subunit into bound ADP and Pi promotes ATP formation
   - F1 may a also works in reverse to hydrolyze ATP and pump out protons depending on proton flow direction