Electron Transport Chain Flashcards
What molecules from the TCA cycle are used in the ETC?
electrons stored in NADH and FADH2
Why are the results of poisoning by agents that bind and inhibit electron carriers in the ETC similar to asphyxiation?
Because when the ETC is unable to function, NADH builds up and inhibits the TCA (aerobic metabolism) and anaerobic metabolism is the only option for ATP production, even when oxygen is available.
How does the ETC function overall to create ATP?
Protons are pumped out of the mitochondrial matrix into the intermediate space to create a proton gradient across the membrane, then the protons move across the gradient through ATP synthase to provide energy for ADP to be phosphorylated into ATP.
What happens to oxygen during ETC?
reduced to water.
How does carbon monoxide and other toxic compounds inhibit ETC?
Inhibits Complex IV (cytochrome oxidase), which takes O2 and reduces it to H2O. If this is inhibited, protons are allowed to flow back into the mitochondrial matrix, bypassing ATP synthase.
What do uncouplers do?
disconnect the processes of electron transport and diffusion of protons through the ATP synthase by dissipating the proton gradient, causing the protons to diffuse through the membrane elsewhere, and losing their energy as heat rather than ATP.
How does using uncouplers prevent oxidative damage?
free radicals stimulate uncoupling proteins when the proton gradient excessive, allows protons to bond with free radicals?
What are uncouplers important for?
regulation of energy balance and heat production.
How do uncouplers work?
by creating a pro in the inner mitochondrial membrane that allows protons back into the mitochondrial matrix without passing through ATP synthase
Rotinone & Amytal
inhibits complex I - stops all downstream electron flow and therefore generation of proton gradient and ATP synthesis
Antimycin A
inhibits complex III - stops all downstream electron flow and therefore generation of proton gradient and ATP synthesis
CO, CN, Azide
Inhibit complex IV - stops all downstream electron flow and therefore generation of proton gradient and ATP synthesis
