Two activities to explore photosynthesis.

• Examine photosynthesis in two parts
• Examine one part or both

Photosynthesis I examines the hill reaction in isolated chloroplasts; splitting water to yield oxygen and release hydrogen. The proteolysis of water in the course of the reaction is measurable using a spectrophotometer or by visual examination due to the bleaching of the hydrogen acceptor. The hill reaction is run in the light and in the dark to demonstrate the light dependence of the reaction.

Photosynthesis II examines the phosphorylation of glucose to produce starch in plant cells. Students collect phosphorylase in potato extract and use it to catalyze the synthesis of starch. They learn that starch synthesis requires primer starch to which glucose residues can be added and that inorganic phosphate inhibits starch synthesis.