ETC & Oxidative Phosphorylation

Question 1

How does NADH and FADH2 get into mithocondria?

Answer 1

From glycolysis and enters the mitochondria via
Malate - aspartate shuttle (NADH)
Glycerol 3 phosphate shuttle (FADH2)

also from TCA cycle in mitochondria

Question 2

Complex 1 of ETC does what

Answer 2

NADH donates electrons to complex one and it begins pumping H+ (protons) into intermembrane space

Electrons are then donated to CoQ

Question 3

Complex 2 of ETC does what

Answer 3

FADH2 donates electrons to complex 2 and gives them to CoQ and transports them to complex 3

Question 4

Complex 3 of ETC does what

Answer 4

Once the electrons are recieved, more protons are pumped into intermembrane space

Electrons are then passed to cytochrome C and then passed to complex 4

Question 5

Complex 4 of ETC does what

Answer 5

Once electrons are received, oxygen acts as the final electron acceptor and pumps protons into intermembrane space

Question 6

Complex 5 of ETC does what

Answer 6

The protons return to the matrix through complex 5 (or ATP synthase) synthesizing ATP

Question 7

What are the major inhibitors of ETC?

Answer 7

Complex 1: Rotenone

Complex 3: Antimycin “An-3-mycin”

Complex 4: Cyanide, CO, Azide

Question 8

What are the major inhibitors of oxidative phosphorylation?

Answer 8

oligomycin
uncouplers
atractyloside

Question 9

What are uncouplers?

Answer 9

Agents that lead to the leakage of protons back into mitochondrial matrix

Abolish electrochemical gradient

Energy produced in ETC is released as heat leading to hyperthermia

Present in brown adipose tissues

Question 10

What is oligomycin?

Answer 10

Binds to ATP synthase and closes proton channel

Preventing re-entry of protons into mitochondrial matrix

Question 11

What is atractyloside?

Answer 11

Inhibits ATP transport from matrix across inner mitochondrial membrane