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The only major component of most food which contains nitrogen is protein (fat, carbohydrate and dietary fiber do not contain nitrogen). If the amount of nitrogen is multiplied by a factor depending on the kinds of protein expected in the food the total protein can be determined. This value is known as the "crude protein" content.
Ubiquitous, essential for all forms of life; all proteins and nucleic acids contain substantial amounts of nitrogen. [11] Toxic in some forms. [11] osmium: 76: 1a: None known. [11] Osmium is very rare, substantially more so than any element essential to life. [3] The oxide is toxic to humans. [11] oxygen: 8: 5
Proteins are the basis of many animal body structures (e.g. muscles, skin, and hair). They also form the enzymes which control chemical reactions throughout the body. Each molecule is composed of amino acids which are characterized by the inclusion of nitrogen and sometimes sulfur. The body requires amino acids to produce new proteins (protein ...
Nitrogen is a fundamental chemical component of amino acids, the molecular building blocks of protein. As such, nitrogen balance may be used as an index of protein metabolism. [1] When more nitrogen is gained than lost by an individual, they are considered to have a positive nitrogen balance and be in a state of overall protein anabolism.
The nitrogen compounds through which excess nitrogen is eliminated from organisms are called nitrogenous wastes (/ n aɪ ˈ t r ɒ dʒ ɪ n ə s /) or nitrogen wastes. They are ammonia, urea, uric acid, and creatinine. All of these substances are produced from protein metabolism.
By contrast, eukaryotic cells are larger and thus contain much more protein. For instance, yeast cells have been estimated to contain about 50 million proteins and human cells on the order of 1 to 3 billion. [43] The concentration of individual protein copies ranges from a few molecules per cell up to 20 million. [44]
The stable isotope composition of amino acids refers to the abundance of heavy and light non-radioactive isotopes of carbon (13 C and 12 C), nitrogen (15 N and 14 N), and other elements within these molecules. Amino acids are the building blocks of proteins.
Nitrogen can be fixed by lightning converting nitrogen gas (N 2) and oxygen gas (O 2) in the atmosphere into NO x (nitrogen oxides). The N 2 molecule is highly stable and nonreactive due to the triple bond between the nitrogen atoms. [75] Lightning produces enough energy and heat to break this bond [75] allowing nitrogen atoms to react with ...