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An increase in the atmospheric CO₂ level increases the rate of photosynthesis - VCE - SSCE Biology - Question 8 - 2014 - Paper 1
Question 8
An increase in the atmospheric CO₂ level increases the rate of photosynthesis. The rate of photosynthesis increases because - the rate of the light-independent rea... show full transcript
Worked Solution & Example Answer:An increase in the atmospheric CO₂ level increases the rate of photosynthesis - VCE - SSCE Biology - Question 8 - 2014 - Paper 1
Step 1
the rate of the light-independent reactions on the thylakoid membranes of the chloroplasts increases.
Answer
As CO₂ levels rise, it leads to an increase in the rate at which light-independent reactions, or the Calvin cycle, occur on the thylakoid membranes. This is primarily due to more CO₂ being available for fixation, increasing glucose production.
Step 2
water loss from the leaf decreases, resulting in the availability of water for photosynthesis increasing.
Answer
Higher atmospheric CO₂ can encourage stomatal closure to prevent excessive water loss. When stomata are partially closed, less water exits, ensuring that enough water remains in the plant system for optimal photosynthesis.
Step 3
the increased CO₂ level lowers the pH inside the chloroplasts and increases the rate of enzyme-catalysed reactions.
Answer
Elevated CO₂ concentrations can influence the internal acidity (lower pH) within chloroplasts, which enhances enzyme activities related to photosynthesis, thereby increasing the overall efficiency of the process.
Step 4
the rate of the light-independent reactions in the stroma increases with the increase in CO₂ level.
Answer
Increased CO₂ availability accelerates the stroma's light-independent reactions, as more RuBisCO enzyme is engaged in carbon fixation, leading to a higher production rate of carbohydrates.