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Pie charts of typical human body composition by percent of mass, and by percent of atomic composition (atomic percent) Body composition may be analyzed in various ways. This can be done in terms of the chemical elements present, or by molecular structure e.g., water , protein , fats (or lipids ), hydroxyapatite (in bones), carbohydrates (such ...
Carbon is a key element to all known life. It is in all organic compounds, for example, DNA, steroids, and proteins. [6] Carbon's importance to life is primarily due to its ability to form numerous bonds with other elements. [17] There are 16 kilograms of carbon in a typical 70-kilogram human. [18] Silicon-based life's feasibility is commonly ...
Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in crystalline structure.. Allotropy or allotropism (from Ancient Greek ἄλλος (allos) 'other' and τρόπος (tropos) 'manner, form') is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements.
Lonsdaleite is an allotrope sometimes called "hexagonal diamond", formed from graphite present in meteorites upon their impact on the earth. The great heat and pressure of the impact transforms the graphite into a denser form similar to diamond but retaining graphite's hexagonal crystal lattice. "Hexagonal diamond" has also been synthesized in ...
Biomolecules are an important element of living organisms. They are often endogenous, [2] i.e. produced within the organism, [3] but organisms usually also need exogenous biomolecules, for example certain nutrients, to survive. Biomolecules and their reactions are studied in biology and its subfields of biochemistry and molecular biology.
This soft, brittle allotrope of arsenic has a steel gray, metallic color, and is a good conductor. [2] The rhombohedral form of this allotrope is analogous to the phosphorus allotrope black phosphorus. In its α-form, As 6 rings in chair confirmations are condensed into packed layers lying perpendicular to the crystallographic c axis. Within ...
These can be inorganic (for example, water and metal ions) or organic (for example, the amino acids, which are used to synthesize proteins). [7] The mechanisms used by cells to harness energy from their environment via chemical reactions are known as metabolism. The findings of biochemistry are applied primarily in medicine, nutrition, and ...
In addition to the allotropes, each allotrope often exists in polymorphs (different crystal structures of the same covalently bonded S n molecules) delineated by Greek prefixes (α, β, etc.). [ 2 ] Furthermore, because elemental sulfur has been an item of commerce for centuries, its various forms are given traditional names.