Photosynthesis simulations

Principles of Biology
Photosynthesis Simulation
Name:
You will be examining photosynthesis in an aquatic plant using dissolved oxygen.
Go to the cell energy simulation at Biology Simulations.
I. Background
Plants perform both photosynthesis and cellular respiration.
1. How will photosynthesis affect oxygen levels?
2. How will cellular respiration affect oxygen levels?
II. Respiration
Find the respiration for the plant.
1. Set the fish number to 0 and the plant number to 1.
2. Set the light intensity to 0% (With no light, there will be no photosynthesis and all changes to oxygen will be due to respiration).
3. Leave the other variables at the default values (25 degrees, white light)
4. Run the simulation three times, recording the starting and ending oxygen values in the table.
5. Find the average difference to determine the respiration per hour.
Trial
DO Start
DO End
DO Difference
1
2
3
Average
Average DO Difference = Respiration / hour
Respiration / hour =
III. Light Intensity
Experimental Question: How does light intensity affect oxygen production?
1. Write your hypothesis.
Hypothesis:
2. Set the fish number to 0 and the plant number to 1. Leave the other variables at the default values (25 degrees, white light).
3. Set the light intensity to 100%.
4. Record the starting and ending oxygen values.
5. Repeat steps 3 and 4 for 80%, 60%, 40%, and 20%.
6. Calculate and record the DO difference, Oxygen (O2) production (in 60 minutes), and Oxygen production per minute.
Light Intensity (%)
DO start
DO end
DO Difference
O2 Production*
O2 Production/min
100
80
60
40
20
*O2 Production = DO Difference + Respiration
7. Write a sentence conclusion.
8. Write a paragraph explaining your conclusion in terms of the process of photosynthesis.
IV. Light Color
Experimental Question: How does light color affect oxygen production?
1. Write your hypothesis.
Hypothesis:
2. Set the fish number to 0 and the plant number to 1. Leave the other variables at the default values (100% light intensity, 25 degrees).
3. Set the light color to white (combination of all wavelengths/colors).
4. Record the starting and ending oxygen values.
5. Repeat steps 3 and 4 for violet, blue, green, yellow, orange, and red light.
6. Calculate and record the DO difference, Oxygen (O2) production (in 60 minutes), and Oxygen production per minute.
Light Color
DO start
DO end
DO Difference
O2 Production*
O2 Production/min
White
Violet
Blue
Green
Yellow
Red
*O2 Production = DO Difference + Respiration
7. Write a sentence conclusion.
8. Write a paragraph explaining your conclusion in terms of the process of photosynthesis.
V. Temperature
Experimental Question: How does temperature affect oxygen production?
1. Write your hypothesis.
Hypothesis:
2. Using the procedure from part II (respiration) find the plant respiration for 15, 20, 30, and 35 degrees.
Temperature (C)
Trial 1 DO Difference
Trial 2 DO Difference
Trial 3 DO Difference
Average (Respiration/Hour)
15
20
30
35
3. Set the fish number to 0 and the plant number to 1. Leave the other variables at the default values (100% light intensity, white light).
4. Set the temperature to 15 degrees.
5. Record the starting and ending oxygen values.
6. Repeat steps 3 and 4 for 20, 25, 30, and 35 degrees.
7. Calculate and record the DO difference, Oxygen (O2) production (in 60 minutes), and Oxygen production per minute. For respiration, use the value determined for each temperature.
Temperature (C)
DO start
DO end
DO Difference
O2 Production*
O2 Production/min
15
20
25
30
35
*O2 Production = DO Difference + Respiration
8. Write a sentence conclusion.
9. Write a paragraph explaining your conclusion in terms of the process of photosynthesis.

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