Question

Oxygen is harmful to:

• A. Ferns
• B. Nitrogen fixing bacteria
• C. Chara
• D. Mango tree

Answer 1

The correct option is B

Nitrogen fixing bacteria

The correct answer is B: Nitrogen-fixing bacteria

Explanation for Correct answer:

Oxygen :

The oxygen gas is the most essential component of various biomolecules such as carbohydrates, lipids, proteins, and nucleic acids; it is present about 21% in the atmosphere.

Oxygen is harmful to Nitrogen-fixing bacteria :

1. 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.
2. The Nitrogen-fixing bacteria are generally found in absence of oxygen
3. 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.
4. The presence of oxygen interferes with nitrogen fixation by degrading nitrogenase enzymes so some bacteria

The correct answer is an option (B).