When isolated chloroplasts are incubated with the artificial electron acceptor 2,6-dichlrophenol-indophenol (DCPIP) and then illuminated with red light, DCPIP (dark blue color) is reduced to DCPIPH2 (clear color). During illumination, oxygen is released, but no NADP+ is reduced to NADPH.

A. From your knowledge of the Hill Reaction, please explain these results.

B. Would you expect this reaction to be inhibited by the herbicide DCMU?

C. What would happen if the uncoupler ammonium chloride were added to the reaction mixture?