National Standards for Grade Levels 9-14
 
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. Required, but not included: centrifuge, blender, spectrophotometer (optional), a light source, glassware, and fresh spinach or lettuce leaves. Allow a one hour lab period for experimentation. Designed for 24 students working in groups of four.