Question

Which one converts nitrite to nitrate?
(a)Nitrosomonas
(b)Nitrobacter
(c)Azotobacter
(d)Rhizobium

Answer 1

Hint: They are a genus comprising rod-shaped, gram-negative, and chemoautotrophic bacteria, and play an important role in the nitrogen cycle. These are non-motile and reproduce through budding or by binary fission. Their cells are obligate aerobes and have a doubling time of about 13 hours.

Complete answer:
Nitrification is the process that converts ammonia to nitrite then to nitrate and is another important step within the global nitrogen cycle. Most nitrification takes place aerobically and is administered completely by prokaryotes. Nitrosomonas bacteria primarily change nitrogen gas to nitrite and later Nitrobacter converts nitrite to nitrate, a plant nutrient. Plants absorb ammonium and nitrate during the assimilation process, after which they're converted into nitrogen-containing organic molecules, like amino acids and DNA.

Additional Information: Importance of the nitrogen cycle is-
1. Assist plants to manufacture chlorophyll from the nitrogen compounds.
2. Assist in changing inert nitrogen gas into a utilizable form for the plants by the biochemical method.
3. In the method of ammonification, the bacteria assist in decaying the animal and plant matter, which obliquely used to wipe up the environment.
4. Nitrates and nitrites are released into the soil, which assists in improving the soil with important nutrients needed for cultivation.
5. Nitrogen is an internal component of the cell and it forms many important compounds and biomolecules.
Nitrogen is additionally cycled by human activities like the combustion of fuels and therefore the use of nitrogen fertilizers. These processes increase the amount of nitrogen-containing compounds within the atmosphere. The fertilizers containing nitrogen are washed away in lakes and rivers and lead to eutrophication.
So, the correct answer is ‘Nitrobacter’.

Note: -Nitrogen is vast in the atmosphere, but it is not utilizable to plants or animals unless it is changed into nitrogen compounds.
-Nitrogen-fixing bacteria have a key function in fixing the atmospheric nitrogen into nitrogen compounds that can be utilizable by the plants.
-The plants soak up the utilizable nitrogen compounds from the soil by their roots. Then, these nitrogen compounds are used for the assembly of proteins and other compounds within the cell.
-Denitrification is the process in which the nitrogen compounds make their way back into the atmosphere by converting nitrate into gaseous nitrogen.