Lab Primer: Photosynthesis
Photosynthesis Lab Copy
Notes on Data Collection & Analysis (You need this too!)
Living systems require free energy and matter to maintain order, to grow, and to reproduce. Energy deficiencies are not only detrimental to individual organisms, but they cause disruptions at the population and ecosystem levels. Organisms employ various strategies that have been conserved through evolution to capture, use, and store free energy. Autotrophic organisms capture free energy from the environment through photosynthesis and chemosynthesis, whereas heterotrophic organisms harvest free energy from carbon compounds produced by other organisms. In multicellular plants, photosynthesis occurs in the chloroplasts within cells. The process of photosynthesis occurs in a series of enzyme-mediated steps that capture light energy to build energy-rich carbohydrates.
In the first part of the lab, you'll learn how to measure the rate of photosynthesis indirectly by using the floating leaf disk assay (FLDA) to measure oxygen production.
In the floating leaf disk assay, a vacuum is used to remove trapped air and
infiltrate the interior of plant (leaf) disk samples with a solution containing bicarbonate ions that serve as a carbon source for photosynthesis. The infiltrated leaves sink in the bicarbonate solution. When placed in sufficient light, the photosynthetic processes then produce oxygen bubbles that change the buoyancy of the disk, eventually causing them to rise.
We'll then go through a brain storming session to come up with ideas for factors that could effect photosynthetic rates. You'll already have the technique down, so it'll be time to test your own idea.
Here's a video from Paul Andersen describing the lab. Some of the methods he describes are slightly different from the ways we'll do it. Be aware of that fact as you watch the video. When you're done, complete the pre-lab quiz below.
Investigation 5 - Photosynthesis (For Reference)