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Multiple Choice
Why do high oxygen levels inhibit photosynthesis in plants?
A
High oxygen levels increase the rate of carbon fixation by Rubisco.
B
High oxygen levels cause the breakdown of glucose produced during photosynthesis.
C
High oxygen levels increase photorespiration, which competes with photosynthesis and reduces its efficiency.
D
High oxygen levels directly block the absorption of light by chlorophyll.
Verified step by step guidance
1
Understand the role of Rubisco in photosynthesis: Rubisco is an enzyme that catalyzes the fixation of carbon dioxide during the Calvin cycle. However, Rubisco can also bind to oxygen instead of carbon dioxide, leading to a process called photorespiration.
Learn about photorespiration: Photorespiration occurs when Rubisco binds to oxygen instead of carbon dioxide. This process consumes energy and releases fixed carbon as CO₂, reducing the efficiency of photosynthesis.
Analyze the impact of high oxygen levels: High oxygen levels increase the likelihood of Rubisco binding to oxygen rather than carbon dioxide, thereby increasing the rate of photorespiration.
Understand the competition between photorespiration and photosynthesis: Photorespiration competes with photosynthesis by using resources (ATP and NADPH) that would otherwise be used for carbon fixation, thus reducing the overall efficiency of photosynthesis.
Conclude why high oxygen levels inhibit photosynthesis: High oxygen levels increase photorespiration, which competes with photosynthesis and reduces its efficiency, making it harder for plants to produce glucose and other energy-rich molecules.