Featured in PASCO’s Advanced Biology through Inquiry Teacher Guide
This manual features 22 challenging, standards-based, inquiry lab activities for AP, IB, and honors programs.
Measure the rate of photosynthesis of a leaf using the carbon dioxide gas sensor.
Plants and other producers utilize the sun's energy to build complex organic compounds that serve as a source of energy for the organism. Chloroplasts are the site of this energy capture and biosynthesis. Chlorophyll and other pigment molecules play a vital role in the light reactions of photosynthesis, capturing energy that drives an electron transport chain and ATP synthesis. Ultimately, through light-independent reactions, the chemical energy is transferred and stored within molecules such as glucose. This entire process is summarized by the chemical equation:
6CO2 + 6H2O → C6H12O6 + 6O2
The uptake of carbon dioxide is an indication that photosynthesis is occurring within the chloroplasts of a leaf. The reactions that fix carbon into organic compounds depend on the products of the light reactions and are therefore dependent on the absorption of light by pigments.\ While sunlight is composed of many different wavelengths of light, those wavelengths are not equally available to a plant. This investigation compares the amount of photosynthesis that occurs when different colors of light are provided to a plant.
In this lab, students test the effect of light color on the rate of photosynthesis. Given the equation for photosynthesis, students can determine that either a carbon dioxide gas sensor or an oxygen gas sensor would be appropriate equipment for determining photosynthetic rate. 6CO2 + 6H2O → C6H12O6 + 6O2 For this investigation, a carbon dioxide gas sensor is used to determine the rate of uptake of CO2 by spinach leaves. Students first test the change in carbon dioxide concentration caused by photosynthesis occurring in the leaves under red light. These results are then compared to the rate of photosynthesis under green light.
ME-6936 Metabolism Chamber
This experiment may require software and an interface for data collection.