in classic experiments that helped convince investigators that the proton, artif
ID: 55709 • Letter: I
Question
in classic experiments that helped convince investigators that the proton, artificial membrane vesicles were reconstituted with purified bacteriorhodopsin (which is a light driven H+ pump from a photosynthetic bacterium) and purified ATP synthase from ox heart mitochondria. in these vesicles the membrane complexes are oriented so that the protons are pumped into the vesicle and ATP synthesis occurs on the outer surface. when ADP and Pi were added to the medium surrounding the vesicles and the vesicles were illuminated with appropriate light, the interior of the vesicles became acidic and ATP was produced.
please answer A, B, and C so I can get a better understanding of this question. I really need help here. the questions are in the photo
Explanation / Answer
2 .If bacteriorhodopsin was randomly oriented, you would expect much less ATP to be synthesized. In vesicles with
equal numbers of oppositely oriented bacteriorhodopsin molecules, no pH difference would be generated upon
exposure to light because the proton pumping in both directions would be equal. In vesicles with an excess of
outwardly directed proton pumps, the pH difference would be in the wrong direction to be utilized by ATP synthase
and thus, no ATP would be made. In vesicles with an excess of inwardly directed proton pumps, a pH difference in
the right orientation would be generated; thus, those vesicles would be capable of synthesizing some ATP.
3.If the ATP synthase molecules were randomly oriented, you would still expect ATP to be synthesized, although at
about half the rate. The molecules that were oriented correctly would make ATP; the oppositely oriented ATP
synthase molecules would be inert.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.