Nitrogen cycle Knowledge-Based Practice

Questions

1. 1.

   Which process in the nitrogen cycle refers to the uptake of inorganic nitrogen compounds from the soil by primary producers and their incorporation into organic molecules such as proteins and nucleic acids?

   • A) Denitrification
   • B) Assimilation
   • C) Nitrification
   • D) Ammonification
2. 2.

   Which process in the nitrogen cycle is responsible for converting inert atmospheric nitrogen gas ($\text{N}_2$) into ammonia ($\text{NH}_3$) or related compounds that can enter biological food webs?

   • A) Nitrogen fixation
   • B) Denitrification
   • C) Nitrification
   • D) Assimilation
3. 3.

   Which process in the nitrogen cycle refers to the conversion of organic nitrogen from dead organisms and metabolic wastes into ammonia or ammonium ions by decomposers?

   • A) Ammonification
   • B) Assimilation
   • C) Denitrification
   • D) Nitrogen fixation
4. 4.

   Which process in the nitrogen cycle converts nitrates in the soil back into atmospheric nitrogen gas ($\text{N}_2$) under anaerobic conditions?

   • A) Denitrification
   • B) Nitrogen fixation
   • C) Ammonification
   • D) Assimilation
5. 5.

   Which biological process in the nitrogen cycle converts ammonium ($\text{NH}_4^+$) ions into nitrite ($\text{NO}_2^-$) and subsequently into nitrate ($\text{NO}_3^-$) ions?

   • A) Nitrification
   • B) Denitrification
   • C) Nitrogen fixation
   • D) Ammonification

Answers and step-by-step solutions appear after you finish the test.