Biology 2201  :  Photosynthesis Lab                             Name: ___________________

Introduction:

Photosynthesis represents one of the most important and fundamental processes encountered in

biology. Photosynthetic organisms, such as plants, algae, and other protists, are able to capture the

energy available in sunlight and use that energy to produce sugars and other carbohydrates from

carbon dioxide in the surrounding environment. There are several types of photosynthetic pigments

found in plants, but chlorophyll is the primary pigment involved in photosynthesis. Chlorophyll is greenish in color and thus absorbs most colors of light except for green and shades of yellow. Most plants also contain accessory pigments, such as carotenes and xanthophylls, which serve to absorb other colors of light and broaden the spectrum of light used to drive the photosynthetic reactions. The amount of carbon dioxide in the atmosphere, and thus available for photosynthesis, has received a lot of attention during the past few decades. Carbon dioxide is considered a "greenhouse gas" and increasingly high levels of carbon dioxide are thought to contribute to global warming. Since plants remove carbon dioxide from the air, the relationship between photosynthetic rates and carbon dioxide levels represents an intriguing area of research.

Hypotheses:

A) Which Native Habitat will result in the highest amount of Photosynthesis?  (Circle One)

Rain Forest Floor                     Coast                           Desert

B) Which CO2 level will result in the highest amount of Photosynthesis?  (Circle One)

274ppm                       370ppm                       740ppm                       1000ppm or above

C) Which Light Color will result in the highest amount of Photosynthesis?  (Circle One)

White                           Red                              Blue                 Green               Yellow

Procedure: 

1) Go to http://www.biocourse.com/biolabs/version3/photosynthesis/index.html

2) In the Biolabs Section Click on Photosynthesis.

3) Click Continue until you get to a graph with three tabs at the top.  The Tabs are Native Habitat, CO2 level and Light Color

----Native Habitat----

1) Select Each type of Native Habitat and Click on the Graph Data Button.

2) Complete the Results Section for ----Native Habitat---- below on the sheet.

3) Click the Clear Data Button

----CO2 Levels----

1) Select each CO2 Level and Click on the Graph Data Button.

2) Complete the Results Section for ----CO2 Levels---- below on the sheet.

3) Click the Clear Data Button

----Light Color----

1) Select each light color and Click on the Graph Data Button.

2) Complete the Results Section for ----Light Color---- below on the sheet.

Results:

----Native Habitat----

Rank the three habitats in terms of the Level of Photosynthesis that Occurred as shown in the graph.

____________________        _______________________            __________________________

---CO2 Levels----

Rank the CO2 Levels in terms of the Level of Photosynthesis that Occurred as shown in the graph.

______________           ____________                  ____________               ______________

----Light Color----

Rank the Light Colors in terms of the Level of Photosynthesis that Occurred as shown in the graph.

______________        ____________     ____________       ___________      ______________

Conclusions / Data Analysis:

1) Compare your hypotheses with your Results.  Were they in agreement or different for each variable?

----Light Color----     Results (Proved / Did Not Support) My Hypothesis

---CO2 Levels----       Results (Proved / Did Not Support) My Hypothesis

----Native Habitat----  Results (Proved / Did Not Support) My Hypothesis

2) Explain why the photosynthetic rates level off on each graph?

3) Photosynthesis is how plants store energy in sunlight as sugars.  Which Light Color, CO2 Level and Native Habitat would result in the greatest increase in plant biomass?

Light Color----__________     CO2 Levels----__________     Native Habitat---________________

4) Carbon dioxide is a greenhouse gas that contributes to global warming. Do the results indicate that plants might be able to reduce carbon dioxide levels by increasing the amount of photosynthesis taking place?

5) Chlorophyll appears green in color, does it absorb green light wavelengths or reflect green light? _______

6) Given that many plants have green colored leaves during summer and lose their color in fall comment on the value of chlorophyll to a plant.

7) Is any single color of light as effective as white light in driving photosynthesis? Explain.