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Biology

Biology Lab: AP Lab #5 - Measuring Dissolved Oxygen Produced by Photosynthesis

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Lab Exercise

Biology Lab: Oxygen Production in Photosynthesis

Concept: The process of photosynthesis requires energy in the form of light to drive the reactions that reconfigure CO2 and H2O to produce glucose and oxygen gas (O2). The rate at which oxygen is produced can be used ot measure the rate of the photosynthetic process.

Goal: To determine how availability of light affects the rate of photosynthesis by measuring oxygen production.

AP STUDENTS Please read through the AP Labortory Manual, Laboratory #5, Photosynthesis. If you have access to the equipment and materials used in the lab, please perform the lab as indicated in the Manual. If not, you may use the alternate lab below. Complete the Lab Manual worksheets and submit your data to the Moodle Biology Website for comparison with the work of your fellow students.

Alternate Experiment Option #1

Perform Illustrated Guide to Home Biology Experiments, Lab IV-1 Chlorophyll and Photosynthesis:

Be sure to complete and include in your final report any questions including in the lab instructions.

Alternate Experiment Option #2

If you are unable to obtain all the equipment and materials required by Investigation #6 or the IGHBE lab, you may perform the following alternate lab that uses more readily accessible chemicals and methods to accomplish the same goal. However, since you should be familiar with the AP Lab as designed, please review that investigation in your lab book. You may also wish to review the laboratory setup and procedure for the 2009 version of this lab at The Biology Place website. Click on LabBench, then on Lab #11, Dissolved Oxygen, and step through the lab process. The graphics will help you visualize how the experiment actually is run.

Materials and Equipment

Unfortunately the lab requires a kit to do "correctly" because it trains you on the Winkler method. You may use any method you like to determine the amount of dissolved oxygen in water. Check out the aquarium supply store for possiblities: Oxygen lab tests are available that allow you to do up to 60 tests for under $15 (see North Coast Marines, for example) and are easier to use than the Winkler method.

Procedure

Measure the dissolved oxygen levels in water of different temperatures, of different salt concentrations, and over time with natural water (from a pond or other source likely to support algae) exposed to different levels of light.

You will need to design much of this lab, based on availability of natural water sources.

Report

Write up your lab experience. Be sure to outline your procedure in detail, record your data, and show examples of your analysis.