Procedure II – Respiration Rates – 0% Illumination Data Run
Complete the tables below using your data and information found under the Background tab (see the Summary of Needed Formulas section)
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| Leaf
Sample Type |
Illumination
Level |
Oxygen
Concentration Change Data (ppm) |
Elapsed
Time (s) |
Oxygen
Change Rate (ppm/s) |
| Sun-
Adapted |
0% | -12.97 | 40 | |
| Shade-Adapted | 0% | -7.78 | 40 |
| Leaf
Sample Type |
Illumination
Level |
Carbon Dioxide
Concentration Change Data (ppm) |
Elapsed
Time (s) |
Carbon Dioxide
Change Rate (ppm/s) |
| Sun-
Adapted |
0% | 12.97 | 40 | |
| Shade-Adapted | 0% | 7.78 | 40 |
Observations and Questions
[10] Sample Calculation: Show your oxygen change rate calculation for the Sun-Adapted data run.
[11] Sample Calculation: Show your carbon dioxide change rate calculation for the Shade-Adapted data run.
[12] What would be the photosynthesis rate if you measured it at 0% illumination in Procedure II? Explain your answer. Cite your results from Procedure I to assist with your explanation.
[13] Cite your results for the change in carbon dioxide concentration in Procedure II as a reference and compare the rates of cellular respiration for sun-adapted and shade-adapted leaves. Explain the biological principles/bases underlying this comparison.
Procedure III – Low-Light Net Photosynthesis Rates – 15% Illumination
Complete the table below using your data and information found under the Background tab (see the Summary of Needed Formulas section)
| Leaf
Sample Type |
Illumination
Level |
Oxygen
Concentration Change Data (ppm) |
Elapsed
Time (s) |
Oxygen
Change Rate (ppm/s) |
| Sun-
Adapted |
15% | 4.42 | 40 | |
| Shade-Adapted | 15% | 7.59 | 40 |
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Observations and Questions
[14] Sample Calculation: Show your oxygen change rate calculation for the Sun-Adapted data run.
[15] Based on the data you collected in Procedures I (100% illumination) and III (15% illumination), which system of leaves produces the most oxygen: Sun-adapted or shade-adapted? Explain how your results support your answer.
[16] Are your results from Procedure II and Procedure III consistent with research findings that there are differences in chlorophyll production and enzyme activity between shade-adapted leaves and sun-adapted leaves? Explain your reasoning. Cite your results from Procedure II and Procedure III to support your explanation.
Procedure I – 100% Illumination
Procedure II – 0% Illumination
Procedure III – 15% Illumination
