Question

The comammox bacteria play a role in nitrification and therefore in the nitrogen cycle. Other microbes, with distinct ecological niches, also participate in the nitrogen cycle. The metabolic reactions involving nitrogen that bacteria perform include: nitrogen fixation (N₂ → NH₃), nitrification (NH₃ → NO₃^- or NO₂^-), and denitrification (NO₃^- or NO₂^- → NO, N₂O, and N₂), all of which make up the nitrogen cycle. Each of these reactions is carried out by a unique set of microorganisms with a distinct ecological niche.

Drag the appropriate items to their respective bins.

A. microbes that oxidize inorganic nitrogen compounds B. obligate anaerobes C. chemoorganotrophs D. chemolithotrophs E. obligate aerobes F. facultative aerobes Bin 1. Nitrogen fixation Bin 2. Nitrification Bin 3. Denitrification

Answer 1

Nitrogen Fixation	Nitrification	Denitrification
Microbes that oxidize inorganic nitrogen compounds	Obligate aerobes Chemolithotrophs	Obligate anaerobes Facultative aerobes Chemoautotrophs

The nitrogen fixation is a process that is used by microbes through which inorganic nitrogen compound present in the air is converted into ammonia or NH3. In this process, the nitrogen fixing bacteria is able to fix the atmospheric nitrogen and form ammonia in presence of nitrogenase enzyme.

Denitrification – The process of denitrification is when the nitrate or N03 is reduced and it leads to the production of molecular nitrogen(N2). The obligate aerobes which require oxygen utilize nitrogen by reducing nitrate. Chemolithotrophs are those which use organic reduced organisms as its source of energy and perform nitrogen metabolism through nitrate reduction.

Nitrification – This is the process of oxidation of ammonia or ammonium and converts it into nitrite and then it is converted into nitrate. The obligate anaerobes, facultative aerobes and chemoautotrophs helps in converting ammonia into nitrite.