Multiple Choice Questions on Nitrogen Cycle

1. Which of the following is correct regarding Nitrogen cycle?

a) N₂ cycle is a sedimentary cycle

b) N is the most abundant nutrient for plants 

c) The major reservoir of Nitrogen is atmosphere

d) All of these

2. Nitrogen fixation is the  

a) Conversion of N₂ to NO₃^- and NH₃

b) Conversion of N₂ to N

c) Conversion of N₂ to urea

d)  All of the above

3. Nitrogen accounts nearly 79% of the air. Still Nitrogen is the most limiting nutrient for plant growth because

a) N₂ cannot be directly utilized by plants

b) High energy is required to break triple bond

c) Nitrogen is almost an inert gas as N involved reaction requires extreme conditions such as high temperature

d) All of the above

4. Majority of nitrogen fixation occurs by

a) Biological nitrogen fixing organisms

b) Lightning

c) volcanic eruptions

d) Haber–Bosch process

5. Biological nitrogen fixation is the conversion of

a) Conversion of N₂ to NO₃^- and NH₃

b) Conversion of N₂ to N

c) Conversion of N₂ to urea

d) Conversion of N₂ to NH₃

6. Which of the following is a symbiotic Nitrogen fixing microorganism?

a) Azospirillum

b) Rhizobium

c) Clostridium

d) Nitrococcus

7. The major enzymes involved in biological Nitrogen fixation are

a) nitrogenase and hexokinase

b) nitrogenase and hydrogenase

c) nitrogenase and hydrolyase

d) nitrogenase and peptidase

8. Ammonification is the process of

a) Formation of ammonia from nitrogen by nitrogen fixers

b) Formation of ammonia from amino acids by decomposers

c) Formation of ammonia from nitrates by nitrogen fixers

d)  Formation of ammonia from nitrates by decomposers

9. The conversion of Ammonia (NH₃) to nitrite (NO₂^-) and then to nitrates (NO₃^-)  is called

a) Nitrification

b) ammonification

c) Assimilation

d) denitrification

10. The process that convert nitrates (NO₃^-) back to nitrogen gas (N₂) there by  replenishing N₂ in the atmosphere is called

a) Nitrification

b) Denitrification

c) Deamination

d) Nitrogen fixation

Learn more: Multiple Choice Questions on Biological Nitrogen Fixation

Answers:

1. c) The major reservoir of Nitrogen is atmosphere

2. a) conversion of N₂ to NO₃^- and NH₃

3. d) All of the above

4 . a) Biological nitrogen fixing organisms

5. d) conversion of N₂ to NH₃

6. b) Rhizobium

7. b) nitrogenase and hydrogenase

8. b) formation of ammonia from amino acids by decomposers

9. a) nitrification
10. b) denitrification