Question

Question 30
Oxygen is harmful to:

(a) ferns
(b) nitrogen-fixing bacteria
(c) chara
(d) mango tree

Answer 1

(b) nitrogen-fixing bacteria

Nitrogen-fixing bacteria are found in anaerobic conditions, i.e., in the absence of oxygen. Certain bacteria such as Azotobacter (occur freely in the soil) and Rhizobium (occur in root nodules of leguminous plants), convert the atmospheric nitrogen into water-soluble nitrates. The process of biological fixation of nitrogen is called as nitrogen fixation.
Enzymes required for nitrogen fixation are nitrogenases. These nitrogenases are very susceptible to destruction by oxygen. Many bacteria cease the production of enzymes in the presence of oxygen.