Question
Which one of the following statements is TRUE about leghemoglobin?
The correct answer is
It binds oxygen to protect nitrogenase
Leghemoglobin Function Explained
Leghemoglobin is a protein found in the root nodules of leguminous plants, playing a critical role in the symbiotic relationship between the plant and nitrogen-fixing bacteria (rhizobia).
Key Role of Leghemoglobin
- Oxygen Binding: Leghemoglobin binds to oxygen molecules.
- Nitrogenase Protection: Its primary function is to protect the enzyme nitrogenase from oxygen. Nitrogenase is essential for converting atmospheric nitrogen ($N_2$) into ammonia ($NH_3$), a form usable by plants.
- Enzyme Sensitivity: Nitrogenase is highly sensitive to oxygen and is irreversibly inactivated by it.
- Controlled Environment: By binding oxygen, leghemoglobin maintains a low, controlled oxygen concentration within the nodule, creating an environment suitable for nitrogenase activity while still allowing the bacteria to perform respiration.
Therefore, the statement "It binds oxygen to protect nitrogenase" accurately describes the function of leghemoglobin.
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Important Questions from Nitrogen Fixation
- In leguminous plants, both the rhizobium genes and the plant genes influence nodulation and nitrogen fixation. Which one of the following functions is NOT encoded by the host plant genes?
- In nitrogen fixation, to reduce nitrogen to ammonia, which one of the following shows the correct order of electron flow?
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