Question

-The process of converting ammonia to nitrate by bacteria is known as
A) Ammonification
B) Nitrification
C) Nitrogen fixation
D) Denitrification

Answer 1

Hint: -Plants are known to require nitrogen for synthesis of amino acids and proteins, but they cannot take up nitrogen in the free form. Nitrogen needs to be converted into ammonia and to nitrate to be available to the plants and bacteria help in this conversion.

Complete answer-
The nitrogen to be available to plants undergoes the nitrogen cycle which includes nitrogen fixation, nitrification, ammonification, assimilation and denitrification. Nitrogen fixation is the step where nitrogen is converted into ammonia by the help of nitrogenase enzymes. This step can be carried out by free living nitrogen fixers such as Azotobacter or symbiotic nitrogen fixers such as Rhizobia. The ammonia generated from nitrogen fixation is first converted into nitrates by Nitrosomonas and then converted into nitrate by Nitrobacter and the process is called nitrification. After nitrification the plants take up the nitrogen from the soil and this step is known as assimilation. When the plants and animals die the organic matter decomposes leading to release of nitrogenous compounds into the soil which are then converted into ammonium by the soil bacteria, which is known as ammonification. Finally the nitrogenous compounds from the soil enter back into the atmosphere through the process of denitrification carried out by Pseudomonas and few other bacteria.

So the correct option is B) Nitrification.

Note-
Nitrogen cycle is an important process as nitrogen helps to form important biomolecules, it helps to synthesize chlorophyll which helps in photosynthesis of plants and it also enriches the soil quality as the nitrates and nitrites are released into the soil.