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CHNOPS and CHON are mnemonic acronyms for the most common elements in living organisms. "CHON" stands for carbon, hydrogen, oxygen, and nitrogen, which together make up more than 95 percent of the mass of biological systems.[ citation needed ] "CHNOPS" adds phosphorus and sulfur.
Carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur are the six most important chemical elements whose covalent combinations make up most biological molecules on Earth.[ citation needed ] All of these elements are nonmetals.
| Element | Mass in plants | Mass in animals | Biological uses |
|---|---|---|---|
| Carbon | 12% | 19% | Found in carbohydrates, lipids, nucleic acids, and proteins. |
| Hydrogen | 10% | 10% | Found in water, carbohydrates, lipids, nucleic acids, and proteins. |
| Nitrogen | 1% | 4% | Found in nucleic acids, proteins, some lipids (e.g. sphingolipids) and some polysaccharides (e.g. chitin) |
| Oxygen | 77% | 63% | Found in water, carbohydrates, lipids, nucleic acids, and proteins. |
| Phosphorus | <1% | <1% | Found in lipids, nucleic acids and proteins. |
| Sulfur | <1% | <1% | Found in proteins and some polysaccharides. |
In animals in general, the four elements—C, H, N, and O—compose about 96% of the weight, and major minerals (macrominerals) and minor minerals (also called trace elements) compose the remainder.
Sulfur is contained in the amino acids cysteine and methionine. [1] Phosphorus is contained in phospholipids, a class of lipids that are a major component of all cell membranes, as they can form lipid bilayers, which keep ions, proteins, and other molecules where they are needed for cell function, and prevent them from diffusing into areas where they should not be. Phosphate groups are also an essential component of the backbone of nucleic acids (general name for DNA & RNA) and are required to form ATP – the main molecule used as energy powering the cell in all living creatures. [2]
Most biological molecules are made from covalent combinations of six important elements, whose chemical symbols are CHNOPS. ... Although more than 25 types of elements can be found in biomolecules, six elements are most common. These are called the CHNOPS elements; the letters stand for the chemical abbreviations of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
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