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: -Nitrifying bacteria convert the most reduced form of soil nitrogen, ammonia, into its most oxidized form, nitrate.

Detailed explanation-3: -Answer: True. Some bacteria can convert nitrates present in the soil into free nitrogen by the process known as denitrification.

Detailed explanation-4: -Bacteria that convert atmospheric nitrogen into nitrogen compounds like ammonia are called nitrogen-fixing bacteria. These bacteria make nitrogen available for the plants. These are of 2 types, symbiotic nitrogen-fixing bacteria like Rhizobium and non-symbiotic nitrogen-fixing bacteria like Azotobacter.

Detailed explanation-5: -Rhizobium is the type of bacteria which is found in the roots of leguminous plants and converts atmospheric nitrogen into nitrates.