Final answer:
The nitrogen cycle involves four main steps: nitrogen fixation, decay, nitrification, and denitrification, with microorganisms playing crucial roles in each step. It makes atmospheric nitrogen available to living organisms in a fixed form necessary for creating essential biological compounds. The highlighted false statement in the multiple-choice question is related to the nitrification process.
Step-by-step explanation:
Nitrogen Cycle Steps:
The nitrogen cycle is a key biogeochemical cycle that makes nitrogen available to living organisms. Air contains approximately 78% nitrogen gas (N2), but most organisms require nitrogen in a 'fixed' form such as nitrate (NO3¯), ammonium (NH4*), or urea (NH2)2CO. Microorganisms play a crucial role in converting nitrogen from one form to another in this cycle. The four main steps of the nitrogen cycle are:
- Nitrogen fixation - Certain bacteria and archaea convert atmospheric nitrogen (N2) into ammonium (NH4+), making it accessible to plants.
- Decay - Decomposers break down organic nitrogen from dead organisms back into ammonium (NH4+), once again making it available in the ecosystem.
- Nitrification - Nitrifying bacteria convert ammonium into nitrite (NO2¯) and subsequently into nitrate (NO3¯), which plants can absorb and use.
- Denitrification - Denitrifying bacteria convert nitrate back into gaseous nitrogen (N2), releasing it back into the atmosphere and completing the cycle.
In summary, the nitrogen cycle ensures that nitrogen is continuously cycled and reused within ecosystems, supporting life by contributing to critical biological molecules such as proteins and nucleic acids.
The correct answer to the false statement about the nitrogen cycle from the provided options is 'd'. Nitrification is the process by which ammonium (NH4+) is converted to nitrite (NO2¯) and then to nitrate (NO3¯), not the other way around as stated.
The complete question is: Write the note on nitrogen cycle.