Name:________________________________________________
Photosynthesis Virtual Lab
Score:_________________/30 points
Background: Photosynthesis is a process that some autotrophic organisms (producers)
perform in order to take light energy and store it as chemical potential energy in the
molecule glucose. The overall equation is: 6CO2 + 6H2O (+light energy)  C6H12O6 + 6O2
Objective: Determine how carbon dioxide concentration (in ppm)
and light intensity (in lux) affects the rate of photosynthesis in the
aquatic plant Elodea.
Hypothesis 1: Write a formal hypothesis about how changing the
light intensity will affect the rate of photosynthesis. (1 point)
Hypothesis 2: Write a formal hypothesis about how changing the
carbon dioxide concentration will affect the rate of photosynthesis.
(1 point)
Note: The rate of photosynthesis will be measured in oxygen bubbles per minute. You will be counting
the number of oxygen bubbles produced by the plant over 4 minutes, then dividing this number by 4 to
get the rate per minute. Why does counting oxygen bubbles tell us that photosynthesis is taking
place? (1 point)
Procedure:
1.Go to bhshonorsbio.wikispaces.com click on unit 3 and open the document called photosynthesis
virtual lab.
2. Click the link to http://www.newpathlearning.com/MML/PHOTOSYNTHESIS/files/BubbleLab.swf
3. Click “Prepare plant” to set up the lab
4. Set the CO2 concentration to 0 ppm and the light intensity to 5000 lux
5. Click start and count the number of oxygen bubbles for “4 minutes”
6. Calculate the number of bubbles PER ONE MINUTE (divide bubbles by 4) and record in data table on
the next page.
7. Repeat steps 4-6 for the following CO2 concentration/light intensity combinations:
0 ppm/15000 lux, 0 ppm/25000 lux
300 ppm/5000 lux, 300 ppm/15000 lux, 300 ppm/25000 lux
600 ppm/5000 lux, 600 ppm/15000 lux, 600 ppm/25000 lux
1200 ppm/5000 lux, 1200 ppm/15000 lux, 1200 ppm/25000 lux
Date table: Bubbles produced per minute. (3 points)
Light Intensity
5000 lux
15000 lux
0 ppm CO2
300 ppm CO2
600 ppm CO2
1200 ppm CO2
25000 lux
Analysis questions: Use your data and your notes on photosynthesis to help you answer the
following questions.
1. What happened to the rate of photosynthesis as the light intensity was increased? Use data to support
your answer (2 points)
2. Based on your knowledge of photosynthesis, why did you get the results you described in question 1?
(1 point)
3. What stage of photosynthesis did changing the light intensity directly affect? Why? (2 points)
4. What is the overall purpose of the stage that you described in question 3? (1 point)
5. What happened to the rate of photosynthesis as the carbon dioxide concentration was increased? Use
data to support your answer (2 points)
6. Based on your knowledge of photosynthesis, why did you get the results you described in question 5?
(1 point)
7. What stage of photosynthesis did changing the carbon dioxide concentration directly affect? Why? (2
points)
8. What is the overall purpose of the stage that you described in question 7? (1 point)
9. What is the purpose of photosynthesis in producers? Why do they need to go through this process? (2
points)
10. Where in the plant cell is photosynthesis taking place? Where in this organelle is each stage taking
place? (3 points)
11. What is the role of ATP in photosynthesis? (1 point)
12. What energy transformations are taking place in photosynthesis? (1 point)
Conclusion: Write a brief conclusion in which you address the objective. Include data to back up
your statements and also use your knowledge of photosynthesis to explain your results. Use the
back of this page if you need more space. (5 points)