In the presence of light, DPIP receives reducing electrons from the photosystems (and ultimately from the water) but this does not occur in the dark....

1.   In the presence of light, DPIP receives reducing electrons from the photosystems (and ultimately from the water) but this does not occur in the dark. Explain the role of light energy in this system, how it makes a difference in the reduction of the dye, and how it allows us to measure photosynthesis. (2 points)