Question

Oxygen is harmful for

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

Answer 1

The correct option is B

Nitrogen-fixing bacteria

The correct option is B.

Explanation of the correct option:

1. The bacteria that can convert atmospheric nitrogen into fixed nitrogen are known as nitrogen-fixing bacteria.
2. Examples - Nonsymbiotic bacteria ( Nostoc) and Symbiotic bacteria ( Rhizobium associated with legume plants).
3. In biological nitrogen fixation, prokaryotic organisms fix molecular nitrogen into ammonium ions.
4. The biological process of nitrogen fixation is catalyzed by an enzyme complex called nitrogenase complex.
5. Nitrogenase is located only in the prokaryotes.
6. Nitrogenases are quickly destroyed by oxygen.
7. So, oxygen is harmful to nitrogen-fixing bacteria.

Explanation of the incorrect options:

Option A:

1. Ferns are plants that do not have flowers.
2. Plants need oxygen to survive.
3. Ferns require oxygen for respiration.

Option C:

1. Chara is a freshwater green alga that can be found submerged in ponds, tanks, lakes, and slow-moving water.
2. Chara requires oxygen for their survival.

Option D:

1. Plants need oxygen to survive.
2. The sugars created during photosynthesis are combined with oxygen during the process of respiration in plants to create energy for plant development.
3. Oxygen is not harmful to mango trees.

Final answer: Oxygen is harmful to Nitrogen-fixing bacteria.