AP BIOLOGY

Detailed explanation-1: -For nitrogen to be available to make proteins, DNA, and other biologically important compounds, it must first be converted into a different chemical form. The process of converting N2 into biologically available nitrogen is called nitrogen fixation.

Detailed explanation-2: -Nitrogen fixation is the processes by which atmospheric N2 is converted to any N compound where N has a nonzero oxidation state. Historically, the most common process has been the biologically driven reduction of N2 to NH3 or NH4+.

Detailed explanation-3: -Nitrogen-fixing bacteria in the soil and within the root nodules of some plants convert nitrogen gas in the atmosphere to ammonia. Nitrifying bacteria convert ammonia to nitrites or nitrates. Ammonia, nitrites, and nitrates are all fixed nitrogen and can be absorbed by plants.

Detailed explanation-4: -Biologically: Nitrogen gas (N2) diffuses into the soil from the atmosphere, and species of bacteria convert this nitrogen to ammonium ions (NH4+), which can be used by plants.

Detailed explanation-5: -To be used by plants, the N2 must be transformed through a process called nitrogen fixation. Fixation converts nitrogen in the atmosphere into forms that plants can absorb through their root systems.