Which statement is not true about nitrogen cycle?

Question

Question

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HPSC Assistant Professor 2018 Botany (Official Paper)

Nitrifying bacteria in the soil or in water convert NH4+ to NO2 and NO3+
The reduction of NO3 to NH4+ is catalyzed by two enzymes, nitrate reductase and nitrite reductase.
The enzyme responsible for biological nitrogen fixation is nitrogenase.
The uptake of soil nitrate by root cells occurs via high and low affinity transport systems located in the cell wail.

Answer 1

The correct answer is The uptake of soil nitrate by root cells occurs via high and low affinity transport systems located in the cell wall.

Explanation:

The nitrogen cycle is a crucial biogeochemical cycle in which nitrogen is converted into multiple chemical forms as it circulates among the atmosphere, terrestrial, and marine ecosystems. Key processes include nitrogen fixation, nitrification, and denitrification.
Nitrate uptake by root cells actually occurs via transport systems located in the cell membrane, not the cell wall. This distinction is crucial for understanding how plants assimilate nitrogen from the soil.

Other Options:

Nitrifying bacteria in the soil or in water convert NH₄⁺ to NO₂and NO₃⁺

This statement is true. Nitrifying bacteria such as Nitrosomonas convert ammonium (NH₄⁺) to nitrite (NO₂^-), and Nitrobacter further convert nitrite to nitrate (NO₃^-). This process is crucial for making nitrogen available in a form that plants can uptake.

The reduction of NO₃ to NH₄⁺ is catalyzed by two enzymes, nitrate reductase and nitrite reductase.

This statement is also true. Nitrate reductase and nitrite reductase are the enzymes responsible for the reduction of nitrate (NO₃^-) to ammonium (NH₄⁺), which can then be assimilated into amino acids and other nitrogen-containing compounds in plants.

The enzyme responsible for biological nitrogen fixation is nitrogenase.

This is correct. Nitrogenase is the enzyme complex that enables certain bacteria and archaea to convert atmospheric nitrogen (N₂) into ammonia (NH₃), a form that can be utilized by plants.