Question

based on your results, what can you conclude from this experiment?

a. plants exposed to blue light will show a greater rate of photosynthesis compared to those exposed to green light.

b. plants exposed to green light will show a greater rate of photosynthesis compared to those exposed to blue light.

c. plants exposed to blue and green light will have the same rate of photosynthesis.

Explanation:

Analyze photosynthetic pigments

Using the Light Absorption and Reflection knowledge point

• Chlorophylls \(a\) and \(b\) are the primary pigments driving photosynthesis.
• These pigments absorb light strongly in the blue (\(\sim 430\text{–}450\text{ nm}\)) and red (\(\sim 640\text{–}660\text{ nm}\)) regions of the spectrum.
• Green light (\(\sim 500\text{–}550\text{ nm}\)) is mostly reflected or transmitted rather than absorbed, which is why most plant leaves appear green.

Relate absorption to photosynthetic rate

Using the Action Spectrum of Photosynthesis knowledge point

• The action spectrum of photosynthesis closely matches the absorption spectrum of chlorophyll.
• High light absorption in the blue region translates directly to a high rate of photosynthesis.
• Low light absorption in the green region results in a significantly lower rate of photosynthesis.
• Therefore, plants exposed to blue light will show a greater rate of photosynthesis compared to those exposed to green light.

Answer:

• A. Plants exposed to blue light will show a greater rate of photosynthesis compared to those exposed to green light. (Correct answer)
• B. Plants exposed to green light will show a greater rate of photosynthesis compared to those exposed to blue light.
• C. Plants exposed to blue and green light will have the same rate of photosynthesis.