Daniel Arnon and coworkers carried out experiments with intact, salt-washed chloroplasts to study photophosphorylation. When the chloroplasts were illuminated in the presence of ADP+Pi, ATPADP+Pi, ATP was produced, but oxygen was not produced or nor consumed. ATPATP formation was not accompanied by a measurable electron transport involving any external electron donor or acceptor. The overall reaction for this result is: ADP+Pi⟶hνATPADP+Pi⟶hνATP When NADP+NADP+ was included in addition to the ADP+PiADP+Pi, illumination of the intact chloroplats again resulted in resulted in the photophosphorylation of ADPADP to ATPATP. In addition, the NADP+NADP+ was reduced to NADPH+H+NADPH+H+ and O2O2 was produced. Moreover, the light-induced reduction of NADP+NADP+ was greatly decreased if ADP+PiADP+Pi were ommitted. The equation for this reaction is: NADP++H2O+ADP+Pi⟶hνNADPH+H++ATP+12O 2NADP++H2O+ADP+Pi⟶hνNADPH+H++ATP+12 O2 Briefly describe the mechanism(s) of these two types of photophosphorylation that explain all of these results.