Electron Transport Chain and Oxidative Phosphorylation Flashcards
The energy carried by the NADH and FAD2H molecules can be used for what?
To drive ATP synthesis in the final stage of catabolism- oxidative phosphorylation
Which 3 of the electron transport proteins also called complexes, have the ability to move protons? What is the special name given to these complexes?
1,3 and 4 (only ones that are transmembrane)
Called proton translocating complexes
What is the proton motive force and what does it mean?
The proton translocating complexes transform the chemical bond energy of the electrons into an electro-chemical potential difference of protons. This is known as the proton motive force (p.m.f). The greater the chemical bond energy of the electrons, the more protons that can be translocated and the greater the p.m.f
Why can the electron transport chain process only occur in the presence of oxygen?
Because it is the terminal electron acceptor
How many H+ need to be moved through the ATP synthase complex for the formation of 1 ATP?
2
What effect does the proton motive force have on the production of ATP?
The greater the Pmf the greater thr synthesis
When [ATP] is high, what happens in terms of electron transport and ATP synthesis? (3) (how are they related)
- [adp] is love and the atp synthesise stop (lack of substrate). This prevent the transport of protons back into the mitochondria
- the [h+] outside increases to a level that prevents more protons being pumped
- in the absence of proton pumping electron transport stops
**reverse happens when [atp] is low
What are uncouplers in terms of electron transport and atp synthesis? Give an example
Substances (ie dinitrophenol-slimming acid) that increase the permeability of the inner mitochondrial membrane to protons.
How do uncouplers work?
They increase the permeability of the inner mitochondrial membrane to protons. This enables protons to re-enter the mitochondrial matrix without driving atp synthesis. The two processes are said to be uncoupled and potential energy of the p.m.f is dissipated as heat
When exposed to uncouplers, what is the result in terms of the electron transport chain and atp synthesis?
ETC continues, atp synthesis stops and excessive amounts of heat is generated.
**proton leak normally accounts for 20-25% of the basal metabolic rate
Out of the 5 uncoupling proteins (UCPs), which appears to be the most important?
UCP1, UCP2, UCP3
Where is UCP1 expressed?
In brown adipose tissue
When might an uncoupling protein be beneficial?
When it is expressed in brown adipose tissue and is Involved in non-shivering thermogenesis- enables mammals to survive in cold environments.
What disease has research shown the UCP2 is linked to? Why?
Diabetes, obesity, metabolic syndrome and heart failure (because it is wide spread through the body)
Where is UCP3 found in the body? What is it involved in?
Skeletal muscles, brown adipose tissue and the heart
Modifying fatty acid metabolism and in protecting against reactive oxygen species damages
