ferredoxin m. plastocyanin C. Show the source of electrons at the beginning of each chain. D. Show the path of electrons through each chain. E. Show the final electron acceptor at the end of each chain. F. Show the proton gradient and ATP synthesis. 2. Bacteriorhodopsin is a cell membrane protein from an archaea (Halobacterium halobium) that pumps protons out of the cell against their gradient. The structure of bacteriorhodopsin is shown in Figure 3. Note the retinal molecule embedded within the protein. Retinal can absorb light energy, which provides the energy for moving the protons against their gradient. In 1974, an experiment was done to support the chemiosmotic theory of ATP synthesis. Bacteriorhodopsin was isolated from Halobacteria and the ATP synthase complex was isolated from cow heart muscle. These purified proteins were then reconstituted into artificial phospholipid membranes (liposomes). A diagram of th experiment is shown in Figure 4. Answer these questions about this experiment. A. Detergent was needed to purify the proteins. Explain the cartoon of the detergent in Figure What is the significance of the symbol they used for the detergent? Why is the detergent attached to only specific portions of the bacteriorhodopsin an- ATP synthase? B. When light was shown on these liposomes, the pH of the media that the liposomes were suspended in went down. Explain why. C. The scientists figured out a way to measure production of ATP in the suspension. ATP synthesis occurred only when ADP and Pi were present and light was shown on the suspension. ATP synthesis did not occur in the dark. Explain this result. D. In two sentences, state how this experiment supports the chemiosmotic theory of ATP synthesis. Sentence 1: state the chemiosmotic theory Sentence 2: state how the experiment supports the theory