Which statement is not true about nitrogen cycle?
1
Nitrifying bacteria in the soil or in water convert NH4+ to NO2 and NO3+
2
The reduction of NO3 to NH4+ is catalyzed by two enzymes, nitrate reductase and nitrite reductase.
3
The enzyme responsible for biological nitrogen fixation is nitrogenase.
4
The uptake of soil nitrate by root cells occurs via high and low affinity transport systems located in the cell wail.