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Mineral Nutrition

Nitrogen cycle in nature Practice Questions

20 free Nitrogen cycle in nature practice questions for the NCERT Biology, each with the correct answer and a detailed explanation. Open any question below, or take the full set as an interactive quiz.

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All Nitrogen cycle in nature questions

20 questions
  1. Q1. The process of conversion of atmospheric nitrogen ($N_2$) to ammonia ($NH_3$) is termed as:
  2. Q2. Decomposition of organic nitrogen of dead plants and animals into ammonia is called:
  3. Q3. In the process of nitrification, ammonia is first oxidized to nitrite by which of the following bacteria?
  4. Q4. The conversion of nitrite ($NO_2^-$) to nitrate ($NO_3^-$) during nitrification is catalyzed by:
  5. Q5. Which of the following describes the nature of nitrifying bacteria?
  6. Q6. The process by which nitrates present in the soil are reduced back to gaseous nitrogen ($N_2$) is called:
  7. Q7. Which of the following bacteria are responsible for denitrification?
  8. Q8. The enzyme complex responsible for the reduction of molecular nitrogen to ammonia in biological nitrogen fixation is:
  9. Q9. Which of the following is a free-living, aerobic nitrogen-fixing bacterium?
  10. Q10. The symbiotic nitrogen-fixing bacterium Rhizobium is found in the root nodules of:
  11. Q11. Which microbe forms nitrogen-fixing nodules on the roots of the non-leguminous plant Alnus?
  12. Q12. The pink-colored pigment found in the nodules of leguminous plants, which acts as an oxygen scavenger, is:
  13. Q13. How many molecules of ATP are required for the production of one molecule of $NH_3$ during biological nitrogen fixation?
  14. Q14. During nodule formation, the curling of root hairs is induced by:
  15. Q15. The first stable product of biological nitrogen fixation is:
  16. Q16. At physiological pH, ammonia is protonated to form $NH_4^+$ ions. Most plants absorb nitrogen as nitrates, but if they accumulate ammonia, it becomes:
  17. Q17. In 'Reductive Amination', ammonia reacts with which organic acid to form Glutamic acid?
  18. Q18. The transfer of an amino group from one amino acid to the keto group of a keto acid is called:
  19. Q19. Asparagine and glutamine are two important ______ found in plants that contain more nitrogen than amino acids.
  20. Q20. Some plants, like soyabean, export fixed nitrogen as specialized compounds called: