Question

Artificial, but functioning electron transport chains, can be made by allowing purified membrane lipids to spontaneously form membranes in the presence of the ETC complexes. These artificial cells are called liposomes. The central cavity(we will call it the matrix) of these cells can contain certain molecules dissolved in the aqueous solution. Indicate how many protons could be pumped out of one of these liposome systems that had NADH in the matrix and UQ(coenzyme Q), cytochrome c and Complexes I, III and IV in the membrane. Your answer should be a whole number. O₂ is present.

Answer 1

One NADH molecule pumps out 10H+ ions from this liposome system. From the complex I NADH is oxidised to NAD+ by pumping of 4H+ outside and then the electron is carried to the ubiquinone system and given to the Complex III where another 4H+ ions are pumped out and the electron is further moved to the complex IV where the electron is given to the O2 atom along with 2H+ ions and 2H+ ions are pumped out. Hence a total of 10H+ ions are pumped out.

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