1. Lab 5: Photosynthesis

2. Purpose
To design and conduct an experiment to explore the effect of certain factors, including different environmental variables, on the rate of cellular photosynthesis
To connect and apply concepts, including the relationship between cell structure and function (chloroplasts); strategies for capture, storage, and use of free energy; diffusion of gases across cell membranes; and the physical laws pertaining to the properties and behaviors of gases

3. Background Light Dependent Reactions: make O2 and ATP and NADPH
Calvin Cycle: Makes G3P (Sugars) using CO2
How can we measure the rate of photosynthesis?

4. Procedure Hole punch leaves to make discs
Use syringe to create a vacuum to suck the air out of the mesophyll in the leaves
Put discs (will sink) into two different cups
Control group: water + soap
Experimental group: baking soda + soap
Soap serves as a wetting agent coating the hydrophobic leaf surfaces and allowing the solutions to enter the cell
Baking soda (sodium bicarbonate) serves a source of CO2
Put under light and watch the magic!

5. Measuring stuff!
You will measure the amount of time it takes for the discs to start floating
What makes them float?
Design a graph to show time vs # floating discs

6. Design Your Own Experiment!
The first procedure is for testing under normal circumstances
Then you must design an experiment to test something else
See me for a list of things to test!
Lab write-up will be a Scientific Poster
Present your designed experiment to the class