The process of nitrogen-fixation by bacteria does not take place in the presence of:
The process of nitrogen-fixation by bacteria does not take place in the presence of:
The correct option is B The elemental form of oxygen
The correct answer is option B: Elemental form of oxygen
The explanation for the correct answer:
Nitrogen fixation:
- The process of fixing atmospheric nitrogen into usable forms is termed nitrogen fixation
- The nitrogen fixation takes place by some bacteria which forms a symbiotic association with the plant.
- The Nitrogen-fixing bacteria such as Rhizobium, Azotobacter, and Nostoc convert the atmospheric nitrogen into nitrates and ammonia which can be absorbed by the plants.
- Nitrogen-fixation does not take place in the presence of oxygen
- Because these bacteria have the nitrogenase enzyme which combines gaseous nitrogen in the atmosphere with hydrogen to produce ammonia, which is then further converted to nitrites and nitrates.
- The presence of oxygen interferes with nitrogen fixation by degrading nitrogenase enzymes so some bacteria avoid producing this enzyme in presence of oxygen.
The explanation for the incorrect answer:
Option A: The molecular form of hydrogen
During nitrogen fixation, nitrogen-fixing bacteria combine the atmospheric nitrogen with the hydrogen to form nitrates which are further converted to nitrites and utilized by green plants
Option C: Water
Plants require water during photosynthesis to convert light energy into chemical energy.
Option D: The elemental form of nitrogen:
The elemental form of nitrogen is through the atmosphere and converted into usable forms such as nitrates and nitrites.
Final answer: A correct answer is an option (B)
The elemental form of oxygen
The correct answer is option B: Elemental form of oxygen
The explanation for the correct answer:
Nitrogen fixation:
- The process of fixing atmospheric nitrogen into usable forms is termed nitrogen fixation
- The nitrogen fixation takes place by some bacteria which forms a symbiotic association with the plant.
- The Nitrogen-fixing bacteria such as Rhizobium, Azotobacter, and Nostoc convert the atmospheric nitrogen into nitrates and ammonia which can be absorbed by the plants.
- Nitrogen-fixation does not take place in the presence of oxygen
- Because these bacteria have the nitrogenase enzyme which combines gaseous nitrogen in the atmosphere with hydrogen to produce ammonia, which is then further converted to nitrites and nitrates.
- The presence of oxygen interferes with nitrogen fixation by degrading nitrogenase enzymes so some bacteria avoid producing this enzyme in presence of oxygen.
The explanation for the incorrect answer:
Option A: The molecular form of hydrogen
During nitrogen fixation, nitrogen-fixing bacteria combine the atmospheric nitrogen with the hydrogen to form nitrates which are further converted to nitrites and utilized by green plants
Option C: Water
Plants require water during photosynthesis to convert light energy into chemical energy.
Option D: The elemental form of nitrogen:
The elemental form of nitrogen is through the atmosphere and converted into usable forms such as nitrates and nitrites.
Final answer: A correct answer is an option (B)
