ETC

Question 1

Where is NADH DH (complex I) in the cell

Answer 1

inner mitochondria

Question 2

What inhibits NADH DH

Answer 2

barbituates
insecticides (Rotenone)

Make less ATP bc NADH unable to give electrons to coenzyme Q

Question 3

What does cyanide inhibit in the electron transport chain

Answer 3

cytochrome oxidase (complex IV)

Question 4

What does oligomycin inhibit in the electron transport chain

Answer 4

F0 channel

• H+ cannot move from outside cell back into the mitochondria to make ATP
• pH in matrix goes down, proteins/enzymes don’t work

Question 5

Cytochrome oxidase (complex IV) is inhibited by

Answer 5

cyanide

carbon monoxide

Question 6

How does cyanide inhibit complex IV

Answer 6

it binds and locks complex IV Fe in the +3 state

• electrons cannot flow through the chain and build up
• no proton gradient
• no phosphorylation to make ATP

Question 7

What is the first line treatment in cyanide poisoning

Answer 7

amyl nitrite (oxidizing agent)

turns Hgb from 2+ to 3+ = making methemoglobin
-more methemoglobin than complex IV, cyanide will bind to methemoglobin first

ferric cyanide gets pee’d out in 120 days when RBCs die

Question 8

what is the second line tx for cyanide poisoning

Answer 8

thiosulfate

-will turn cyanide into thiocyanate (less toxic)

Question 9

How does CO inhibit complex IV

Answer 9

locks Fe in the 2+ state

• electrons cannot move onto the oxygen
• build up of electrons
• no ATP

Question 10

What is the effect of 2,4-DNP on the ETC

Answer 10

weak base

• binds to H+ in cytosol and brings into the mitochondria bypassing F0 channel
• uncouples, electrons still flowing but no ATP made
• energy given off as heat (hyperthermia)

Question 11

Besides 2,4-DNP what else is an uncoupler

Answer 11

high dose aspirin

thermogenin

Question 12

What is thermogenin

Answer 12

enzyme in inner layer of mitochondria that makes small channel for H+ to flow from cytoplasm to matrix

-seen in brown adipose tissue in newborns for heat production