Photosynthesis Rate

Photosynthesis Lab

Before you begin, save this Lab Report Template on your computer as LastNameAPBIOPhoto

Read all the instructions below BEFORE you start!

1. Please go to the following website: http://www.biocourse.com/mhhe/bcc/domains/biolabs.xsp 2. Scroll down and click on the link to Photosynthesis. It is the 6th one down on the left.

3. Read the instructions for entering the virtual lab. There is background information in the online lab manual that will be helpful in interpreting your results. Please review the steps in the light and dark reactions of Photosynthesis BEFORE or WHILE you are completing this lab simulation. You may want to have your textbook open to refer to while you do the lab. You may also need to use additional sources of information.

4. Remember to cite ALL external sources that you use, using proper MLA style.

5. YOU DO NOT NEED TO ANSWER THE ONLINE QUESTIONS, but you should think about them as you proceed thorough the lab.

Note: Lab Instructions start on the next page!

Experiment 1: Habitat and Photosynthetic Rates

Predict the relative photosynthetic rates of plants from a shaded rainforest floor, a coastal region with moderate light, and a sunny desert:

Rainforest Prediction: ____________________________________________
Coast Prediction: ________________________________________________
Desert Prediction: _______________________________________________

a. Continue to the simulation screen and click Clear Data and click the Native Habitat tab
b. Select Rainforest floor and then click Graph Data
c. Repeat for Coast and Desert.
d. Record your results in the Table 4-1, reading the data from the online display
e. Graph your data using Create-a-Graph (http://nces.ed.gov/nceskids/graphing/)

Results Experiment 1
Data Table 4.1: Habitat and Photosynthesis at Different Light Intensities

Light Intensity
(foot-candles) Photosynthesis Rate
(mg CO2/g fresh leaf) Rainforest Coast Desert
0
5
10
15
20
25
30
35
40
45
50

Analysis Experiment 1
a. How is photosynthetic rate measured?
b. Explain why the photosynthetic rate is negative at low levels of light intensity.
(HINT: Is there a net uptake or release of CO2 at low light intensity?)
c. Which of the 3 types of plants had the highest photosynthetic and which had the lowest?
d. Did this observation agree with your predictions?
e. Indicate factors that might be associated with the differences in photosynthetic rates in the 3 types of plants.
f. At what light intensity level did photosynthetic rate level off? Was this light intensity the same for all plants?
g. Explain why the photosynthetic rate levels off.
h. Is there a relation between light intensity and leveling off of photosynthetic rates in the different plants?
i. Explain how plants become acclimated to light levels normally found in their native habitat.

Conclusion Experiment 1: Short, testable statement!
(HINT: Rank the plants from high to low photosynthetic rate)
Experiment 2: Light Color and Photosynthetic Rates

Predict the relation of carbon dioxide level and photosynthesis rates:

Prediction: ____________________________________________

a. Click Clear Data and then the CO2 levels tab
b. Select 274 ppm (parts per million) and click Graph Data
c. Repeat with 370, 740, and 1000+ ppm CO2
d. Record your results in the Table 4-2, reading the data from the online display
e. Graph your data using Create-a-Graph (http://nces.ed.gov/nceskids/graphing/)

Results Experiment 2
Data Table 4.2: CO2 Levels and Photosynthesis at Different Light Intensities

Light Intensity
(foot-candles) Photosynthesis Rate
(mg CO2/g fresh leaf) 274 ppm CO2 370 ppm CO2 740 ppm CO2 1000+ ppm CO2
0
5
10
15
20
25
30
35
40
45
50

Analysis Experiment 2
a. What is the relation between CO2 levels and photosynthesis rates?
b. Indicate where and explain why the photosynthesis rates level off at different levels of light intensity.
c. Are CO2 levels a rate-limiting factor? Explain.
d. What is a greenhouse gas?
e. What is global warming?
f. Suggest a possible relation between plant function, greenhouse gases, and global warming.

Conclusion for Experiment 2: Short, testable statement!
(HINT: Indicate the relation of CO2 levels and photosynthesis rate)

Experiment 3
Predict the relation of light color and photosynthesis rates:

Prediction: ____________________________________________

a. Continue to the simulation screen and click Clear Data and then the light color tab
b. Select white light and click Graph Data
c. Repeat with red, blue, green, and yellow light
d. Record your results in the Table 4-3, reading the data from the online display
e. Graph your data using Create-a-Graph (http://nces.ed.gov/nceskids/graphing/)

Results Experiment 3

Data Table 4.3: Light Color Photosynthesis at Different Light Intensities

Light Intensity
(foot-candles) Photosynthesis Rate
(mg CO2/g fresh leaf) White Red Blue Green Yellow
0
5
10
15
20
25
30
35
40
45
50

Analysis Experiment 3
a. Which light is most effective in driving photosynthesis rate?
b. At what light intensity does the photosynthesis rate level off for white light?
c. Why does the photosynthesis rate level off for white light but not for the individual colors?
d. Which colors, other than white, are associated with the highest photosynthesis rate? With the lowest?
e. What colors of light do plant leaves absorb during the growing season?
f. What colors of light do plant leaves reflect during the growing season?
g. How does chlorophyll interact with accessory pigments to broaden the spectrum of light for photosynthesis?

Conclusion Experiment 3: Short, testable statement!
(HINT: Rank the colors from high to low photosynthetic rate)

Reflection: Statement about what you learned from this lab simulation.
(NOTE: The reflection should be AT LEA