Question

Oxygen is harmful for
(A) Ferns
(B) Nitrogen fixing bacteria
(C) Chara
(D) Mango tree

Answer 1

Hint: Oxygen is the important gas which helps in the survival of many organisms. This is used for the respiration used by the metabolism of the organism and the carbon dioxide is released as the result of the metabolism. But it is harmful to some of the organisms also.

Complete answer:
Oxygen deactivates the enzymes that are needed for fixing the nitrogen like nitrogenase reductase. Since it deactivates the enzymes, it also stops the process of nitrogen fixation along these lines. A portion of the nitrogen fixer’s act in anaerobic condition to diminish the degree of oxygen or permit the oxygen to join with leghemoglobin.

Since it stops the nitrogen fixation, the nitrogen fixing bacteria that lives in the roots of the mycorrhiza plants also don’t get enough energy from the plant for its growth. This happens because the symbiotic relationship between the bacteria and the plant fails. The plants from the given options ferns, chara and the mango tree require oxygen for its growth and the process of photosynthesis. But the oxygen is harmful for nitrogen fixing bacteria.

Hence the correct answer is OPTION(B)

Note: The nitrogen fixing bacteria is mainly found in the areas of the anaerobic conditions. The example of this type of organism is rhizobium they found in the roots of the leguminous plants. These plants have mycorrhizal root which maintains the symbiotic relationship between the plants and the bacteria.