AP BIOLOGY

Detailed explanation-1: -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-2: -Plants get the nitrogen that they need from the soil, where it has already been fixed by bacteria and archaea. Bacteria and archaea in the soil and in the roots of some plants have the ability to convert molecular nitrogen from the air (N2) to ammonia (NH3), thereby breaking the tough triple bond of molecular nitrogen.

Detailed explanation-3: -Lightning can also fix nitrogen. The high temperature of a lightning bolt can break the bonds of atmospheric nitrogen molecules. Free nitrogen atoms in the air bond with oxygen in the air to create nitrogen oxides, which dissolve in moisture to form nitrates that are carried to Earth’s surface by precipitation.

Detailed explanation-4: -When lightning strikes, it tears apart the bond in airborne nitrogen molecules. Those free nitrogen atoms then have the chance to combine with oxygen molecules to form a compound called nitrates. Once formed, the nitrates are carried down to the ground by rainfall.

Detailed explanation-5: -A very small amount of nitrogen is fixed via lightning interacting with the air. Once nitrogen is fixed, other types of bacteria convert ammonia to nitrate (NO3‑) and nitrite (NO2–), which can then be used by other bacteria and plants.