Nitrogen is a critical element in life on Earth. It’s essential for plants and animals, and it’s even found in our DNA. Without nitrogen, there would be no plants or animals just dirt, rocks, and maybe some bacteria. Nitrogen is necessary for photosynthesis and other processes, so most organisms have special ways to get it. Nitrogen is present in every cell of every plant and animal. Humans, for example, have about 3 grams of nitrogen per kilogram of body weight. The human body uses about 0.5 g/kg as protein (nitrogen-based) amino acids and converts the rest into ammonia through natural processes such as urea production from ingested proteins (such as meat). However, only a small amount of this ammonia can be directly used by humans. So we get the nitrogen we need from eating plants that have stored it in their leaves as amino acids or converted it into ammonium ions (NH4+). All plants take up nitrates from the soil to produce their amino acids or ammonium ions plants do not directly use nitrate compounds like nitrites or nitric acid to synthesize amino acids or ammonium ions.
What is Nitrogen?
Nitrogen is a non-metallic chemical element that is found in the air, soils, and oceans in the form of free nitrogen, nitrogen oxides, and various types of organic and inorganic compounds. The abundance of nitrogen in Earth’s atmosphere is about 78% by volume, which is about 21% by weight. In the soil, nitrogen is found in organic compounds that are released into the soil by the decomposition of plant and animal remains. Nitrogen is present in all living things as a protein and nucleic acid. It is one of the building blocks of organic compounds, such as amino acids and nucleic acids. Inorganic compounds of nitrogen include salts (e.g., ammonium nitrate, ammonium sulfate, sodium nitrate) and nitrous oxide (N2O).
Why is Nitrogen Important for Life?
Nitrogen is a critical element in life on Earth because it’s essential for the synthesis of amino acids, proteins, and nucleic acids, which are the building blocks of all organisms. Therefore, nitrogen is necessary for the growth of both plants and animals, including humans. Plants use nitrogen to make amino acids, proteins, and enzymes and to form chlorophyll in their leaves. Animals get the nitrogen they need by eating plants or other animals that have stored or ingested nitrogen.
All About Nitrogen Compounds
Nitrogen is a very common element that occurs as an element, in combined forms, and as metabolites in all organisms. The total amount of nitrogen on Earth is constantly cycling between various forms and locations. Nitrogen gas (N2) is the most common form. Nitrogen can also be found in the soil as nitrates, in the ocean as ammonium, and dissolved in water as nitric acid (HNO3). Nitrogen is an important nutrient for plants, animals, and humans. It is used to make proteins and nucleic acids (such as DNA and RNA), which are necessary for life.
How do Organisms Get Their Supply of Nitrogen?
Nitrogen is an essential nutrient obtained from the environment. Organisms either use energy from the sun or get it from the breakdown of other organic materials to transform nitrogen in the soil into a form they can use. Organisms may use other organisms as a source of nitrogen, or they may transform the nitrogen in the soil by microbes. Plants - The biggest consumers of nitrogen are plants, which transform (fix) atmospheric nitrogen via the enzyme nitrogenase into ammonium ions (NH4+). Plants then store this nitrogen in their leaves and other tissues. Animals that eat only plants get their nitrogen from the plants they eat. Animals that eat only other animals get their nitrogen from the ammonium ions in the animals' urine and feces.
Animals that Eat Only Plants
These organisms have developed many different methods to get their nitrogen from plants. Legumes have root nodules that house symbiotic bacteria. These bacteria convert nitrogen gas in the soil into ammonia. The bacteria are then eaten by the plant, and the plant uses ammonia to synthesize amino acids and proteins. Other plants have developed symbiotic relationships with certain fungi. These fungi help the plants break down soil minerals that contain nitrogen, making the nitrogen available to the plant.
Animals that Eat Only Other Animals
These organisms also have various ways of obtaining their required intake of nitrogen. Carnivorous animals such as lions and eagles obtain their nitrogen by eating the flesh of their prey. Omnivorous animals such as pigs, rats, and humans obtain their nitrogen by ingesting plants and other animals.
Animals that Eat Both Plants and Other Animals
These organisms have developed many different methods to get their required intake of nitrogen. Some organisms use a combination of two or more of the methods described above:
- Insects such as aphids and butterflies obtain their nitrogen by ingesting plants and sugars and proteins and nitrogen
- Herbivores such as cows and sheep obtain their nitrogen by ingesting plants and proteins and other animals
- Carnivores such as lions and eagles obtain their nitrogen by ingesting other animals and plants and other animals
- Omnivores such as pigs, rats, and humans obtain their nitrogen by ingesting plants, other animals, and other animals
Nitrogen is an important nutrient for plants and animals. It is used to make proteins and nucleic acids, which are necessary for life. Nitrogen is an essential nutrient obtained from the environment. Organisms either use energy from the sun or get it from the breakdown of other organic materials. There are many different ways to obtain nitrogen. The biggest consumers of nitrogen are plants, which transform atmospheric nitrogen via the enzyme nitrogenase into ammonium ions. Plants then store this nitrogen in their leaves and other tissues. Animals that eat only plants get their nitrogen from the plants they eat. Animals that eat only other animals get their nitrogen from the ammonium ions in the other animals' urine and feces.