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Question
The nitrogen molecules present in the air can be converted into nitrates and nitrites by
Options
a biological process of nitrogen-fixing bacteria present in the soil
a biological process of carbon fixing factor present in the soil
any of the industries manufacturing nitrogenous compounds
the plants used as cereal crops in the field
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Solution
a biological process of nitrogen-fixing bacteria present in the soil
Explanation:
Nitrogen molecules present in the air cannot be used as such by plants and animals and must be converted into biologically 5 acceptable forms. A number of symbiotic and free-living bacteria e.g., Rhizobium, Azotobacter etc. convert nitrogen into ammonia. Most of the ammonium compounds are oxidised by nitrite bacteria (Nitrosomonas and Nitrosococcus) to soluble nitrates, which are further oxidised by nitrate bacteria (Nitrobacter and Nitrocystis) to soluble nitrates.
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RELATED QUESTIONS
Match the following.
| Microorganism | Role Played |
| Nitrosomonas | Nitrogen fixation |
| Azotobacter | Ammonification |
| Pseudomonas species | Nitrification |
| Putrefying bacteria | Denitrification |
How do human activities affect nitrogen cycle?
Which free living microorganism helps in nitrogen fixation?
When we breathe in air, nitrogen also goes inside along with oxygen. What is the fate of this nitrogen?
Match Column - I with Column - II.
| Column - I | Column - II | ||
| (a) | Nitrococcus | (i) | Denitrification |
| (b) | Rhizobium | (ii) | Conversion of ammonia to nitrite |
| (c) | Thiobacillus | (iii) | Conversion of nitrite to nitrate |
| (d) | Nitrobacter | (iv) | Conversion of atmospheric nitrogen to ammonia |
Choose the correct answer from the options given below.
Match Column - I with Column - II.
| Column - I | Column - II | ||
| (a) | Nitrococcus | (i) | Denitrification |
| (b) | Rhizobium | (ii) | Conversion of ammonia to nitrite |
| (c) | Thiobacillus | (iii) | Conversion of nitrite to nitrate |
| (d) | Nitrobacter | (iv) | Conversion of atmospheric nitrogen to ammonia |
Choose the correct answer from the options given below.
In the Nitrification process, the ammonium compounds are oxidised to soluble ______.
The blue-green algae that take part in nitrogen fixation are also called ______.
Assertion (A): Plants and animals can utilize atmospheric nitrogen.
Reason (R): The atmosphere is a rich source of nitrogen.
Consider the following statements. Which of the statements given below is incorect?
