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Lettuce can be cultivated commercially in greenhouses - Scottish Highers Biology - Question 11 - 2023
Question 11
Lettuce can be cultivated commercially in greenhouses. The diagram represents some stages of the light reaction in photosynthesis in lettuce. (a) Describe what hap... show full transcript
Worked Solution & Example Answer:Lettuce can be cultivated commercially in greenhouses - Scottish Highers Biology - Question 11 - 2023
Step 1
Describe what happens to electrons in pigment molecules when light energy is absorbed.
Answer
When light energy is absorbed by pigment molecules, electrons become excited. This excitation leads to the transfer of these energized electrons through the electron transport chain, facilitating the process of photosynthesis.
Step 3
Describe the relationship between light intensity and the yield of lettuce.
Answer
As light intensity increases, the yield of lettuce also increases, reaching a peak at 175 units of light intensity. Beyond this point, the yield remains constant at 1500 g of dry mass per m², indicating that other factors might limit further increases in yield.
Step 4
Name an environmental factor, other than light intensity, which could increase the yield of lettuce produced.
Answer
Environmental factor: CO₂ concentration.
Explanation: An increase in CO₂ concentration enhances the rate of photosynthesis by providing more reactants for the carbon fixation process, specifically for combining with ribulose bisphosphate (RuBP) to produce sugars.