The fluorescent dye, acridine orange, is quenched by H+ ions. Two H+ ions elimin
ID: 179539 • Letter: T
Question
The fluorescent dye, acridine orange, is quenched by H+ ions. Two H+ ions eliminate fluorescence of one acridine molecule. [ Acridine2-(fluorescent) + 2 H+ ––> AcridineH2 (nonfluorescent) ]
Inside-out membrane vesicles of Escherichia coli containing acridine orange quench fluorescence by pumping H+ ions into the vesicle during electron transport. What amount of oxygen atoms (O or O2) would be used up if 40 imoles of acridine orange is quenched and NADH is the source of reducing power?
Hint: Show your calculations. A diagram of electron transport would probably help you figure this out and might help you get more marks.
What effect would this acridine orange have on the amount of ATP synthesised, i.e. ATP production would increase, decrease or stay the same?
Explanation / Answer
The acridine orange is a florescent dye associated with mitochondria. When added to cells in small amounts , results in strong inhibition of ATP synthesis ie reduces the ATP production. When added in large amounts it results in cytotoxicity.