Since all the planets have the same sun, the solar spectrum on the surface of each planet is the same. The solar spectrum does not change over the course of a day. The visible spectrum underneath a plant canopy has some green and lots of far-red light but lacks red or blue light.
Light serves to generate reducing power that is used to fix carbon dioxide.
Light limits the rate of photosynthesis initially but at some point the amount of carbon dioxide becomes limiting. Plant photosynthesis has two photosystems running in series while bacterial photosynthesis only has one photosystem. Bacterial photosynthesis is totally different from plant photosynthesis. Questions 5 through 10 deal with the light dependent reactions of photosynthesis. List two contributing events for the production of a proton gradient across the thylakoid membrane.