Bio Question

[20090900]

---

Members don't see this ad.

Is nitrogen fixing/fixation....

a) N2 --> NH3 (ammonia)
b) N2 ---> NH4 (ammonium)

I've read posts from 2008 but there is a lot of uncertainty. Maybe it's more clear now? Thanks in advanced.

 

[Kingsta2426]

Is nitrogen fixing/fixation....

a) N2 --> NH3 (ammonia)
b) N2 ---> NH4 (ammonium)

I've read posts from 2008 but there is a lot of uncertainty. Maybe it's more clear now? Thanks in advanced.

Its A, nitrogen fixation is converting atmospheric nitrogen to ammonia.

 

[dentalwannabe]

You can remember this by thinking about the initial beneficiaries of N-fixation: plants. Ammonium is an acid and would be harmful to plants if that's what was being presented to plants at their root nodules.

 

[NDPitch]

Its A, nitrogen fixation is converting atmospheric nitrogen to ammonia.

Not according to Cliff's bio. Quote...

Plants absorb nitrogen either as NO3- or NH4+, and animals obtain nitrogen by eating plants or other animals. The stages in the assimilation of nitrogen are as follows...

Nitrogen Fixation: N2 to NH4+ by nitrogen fixing prokaryotes
Nitrification: NH4+ to NO2-, and NO2- to NO3-

 

[aqz]

Nitrogen fixation is fixing N2 into NH3. However, it can also be referred to fixing N2 into NH4+ as well as further into NO2 and finally NO3. The Nitrogen Cycle as a WHOLE converts N2 from the atmosphere into NO3 for plants to absorb.

In between, you have the following possibilities:

Lightning fixation: N2 -> NO3

Decomposers: dead plants/animals/wastes -> NH4+

Decay bacteria: dead plants/animals/wastes -> NH3

Nitrogen fixing bacteria (legume roots): N2 -> NO3 or N2 -> NH4+ and then following:

Nitrite bacteria: NH4+ (from either decomposed NH4+ or nitrogen fixated NH4+) -> NO2- or NH3 -> NO2- and finally

Nitrate bacteria: NO2 ->NO3

Also, some of the NH3 can be denitrified by denitrifying bacteria into atmospheric N2 (back to beginning of the cycle).

Sources: KBB, wikipedia, google.