Metropolitan Community College, Omaha

BIOS 1010

Variables We know that the basic needs for photosynthesis are simple - light, water, and carbon dioxide. If these inputs are available, shouldn’t the plant thrive and make sugar molecules successfully? Not necessarily. A variety of environmental variables can influence the process of photosynthesis. You will examine this idea in the following experiment. To study the chemical process of photosynthesis we need a tool, a way to know that photosynthesis is occurring. We are going to use the floating leaf disk assay to determine if photosynthesis is occurring and its approximate rate. During this assay you will use a sodium bicarbonate solution as your CO2 source. As photosynthesis is occurring in your leaf disk, they will start to float because of the oxygen being produced. However, remember that these leaf disks will also be using the O2 produced by photosynthesis for cellular respiration. Materials: Baking Soda Dish Soap Leaves (Spinach is shown, but anything that is green works) Syringe – (found in the lab kit) Hole Punch (found in the lab kit) Clear container (a drinking glass is shown)