Topic 3: Oxidative Phosphorylation (ETC) Flashcards
What parts of the ETC are soluble?
CoQ and Cyt C
What’s another name for Complex 1?
NADH-Q Reductase
What’s another name for Complex 2?
Succinate Dehydrogenase or FADH2-Q Dehydrogenase
What’s another name for Complex 3?
Cytochrome reductase
What’s another name for Complex 4?
Cytochrome oxidase
What’s another name for Complex 5?
ATP Synthase
What is the final electron acceptor in the ETC?
Oxygen –> Makes water
Can the complexes move throughout the membrane at will?
No the Complexes are fixed. Cyt C and CoQ are soluble and can move.
Describe what happens to NADH when it encounters the ETC.
Complex 1 H+ is removed into the matrix and NAD+ is regenerated while e- continues through the chain–> CoQ –> Complex 3 –> Complex 4 –> Complex 5
The e- moving from complex to complex provides energy for H+’s to be pumped out along the way.
Describe what happens to FADH2 when it encounters the ETC.
Complex 2 H+ is removed in the matrix and FAD+ is regenerated while takes e- continues through the chain–> CoQ –> Complex 3 –> Complex 4 –> Complex 5
The e- moving from complex to complex provides energy for H+’s to be pumped out along the way.
How many ATP are generated per NADH?
2.5 because they enter at Complex 1
How many ATP are generated per FADH2?
1.5 because they enter at Complex 2
Name a couple substances that inhibit Complex 1.
Rotenone (used as fish poison) and Amytal (barbiturate anesthetic)
Name a few substances that inhibit Complex 3.
Antifungals: Antimycin A, Myxothiazol, Stigmatellin
Name a few substances that inhibit Complex 4.
Inorganic molecules: Cyanide, Carbon Monoxide, Sodium azide (antibacterial/antifungal)
What is the Triple Chemiosmotic Gradient?
CONCENTRATION of H+, CHARGE difference established by that, and OSMOTIC pressure as well
How many protons/H+ are pumped out per NADH?
10: 4 at Complex 1; 2 at Complex 3; 4 at Complex 4
How many protons/H+ are pumped out per FADH2?
6: 2 at Complex 3; 4 at Complex 4
How many protons are required for Complex 5/ATP Synthase to generate ATP?
4 Protons per ATP
How many ATP are generated per NADH?
10 protons per molecule/4 protons per ATP = 2.5 ATP per NADH
How many ATP are generated per FADH2?
6 protons per molecule/4 protons per ATP = 1.5 ATP per FADH2
What does Cold Stress stimulate?
Release of Thyroxine which Uncouples the ETC via thermogenin. This is a natural occurrence of uncoupling.
Also, sympathetic release of NorEpinephrine which also activates thermogenin via increased FFA in fat cells.
What is UCP1?
Thermogenin. It is a normal physiological uncoupler of oxidative phosphorylation.
When would you benefit from uncoupling oxidative phosphorylation?
Newborns, hibernating animals, cold adapted animals
Are mitochondrial disease compatible with life?
Nope
Why would you see heat-seeking in a hypothyroid dog?
Lack of thyroxine leads to insufficient response to cold stress –> animal is cold, wants to warm up = heat-seaking
