Q. Select the match ones. I Nitrosomonas – Nitrite to nitrate II Thiobacillus - Denitrification III Nostoc - Free-living nitrogen-fixer IV Azotobacter - Anaerobic nitrogen-fixer
A) I and II
B) III and IV
C) II and III
D) II and IV
Explanation
Nitrate present in the soil is reduced to nitrogen by the process of denitrification. Denitrification is carried by bacteria Pseudomonas and Thiobacillus. A number of cyanobacteria such as Anabaena and Nostoc are free-living nitrogen-fixers. Azotobacter and Beijernickia are free-living nitrogen fixing aerobic microbes. Nitrosomonas and/or Nitrosococcus oxidise $NH_{3}$ to nitrite. The nitrite is further oxidised to nitrate with the help of Nitrobacter and Nitrocystis.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.