MCQs on Nitrogen Cycle

MCQs on Nitrogen Cycle

1. Which of the following statements is correct?
a. Atmosphere is the major reservoir for plants
b. Nitrogen is the most abundant nutrient for plants
c. Nitrogen cycle is a sedimentary cycle
d. All

2. Nitrogen is absorbed by the plants in the form of
a. Ammonium
b. Nitrites
c. Nitrates
d. All

3. Nitrogen fixation is the conversion of
a. N2 to N
b. N2 to NH3
c. N2 to NO3–
d. N2 to urea

4. Important enzymes involved in nitrogen fixation are
a. Nitrogenase and hydrogenase
b. Nitrogenase and hexokinase
c. Nitrogenase and peptidase
d. Nitrogenase and hydrolyase

5. Symbiotic nitrogen-fixing cyanobacteria are not present in
a. Azolla
b. Gnetum
c. Anthoceros
d. Cycas

6. How many molecules of ATP are required to fix one molecule of nitrogen?
a. 12
b. 20
c. 6
d. 16

7. Ammonification is the formation of
a. Ammonia from nitrates by decomposers
b. Ammonia from nitrogen
c. Ammonia from amino acids
d. Ammonia from nitrates by nitrogen fixers

8. Conversion of nitrates to nitrogen is called
a. Ammonification
b. Nitrification
c. Nitrogen fixation
d. Denitrification

9. Conversion of nitrites to nitrates is called
a. Nitrosococcus
b. Clostridium
c. Nitrobacter
d. Nitrosomonas

10. Conversion of ammonia to nitrite and then to nitrates is called
a. Ammonification
b. Denitrification
c. Assimilation
d. Nitrification

Answer Key