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Outline of life forms. The following outline is provided as an overview of and topical guide to life forms: A (also spelled or ) is an that is living, [1][2] such as plants (flora), animals (fauna), and fungi (funga). It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species, [3] are ...
Structure of a typical L-alpha-amino acid in the "neutral" form. Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. [1] Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. [2] Only these 22 appear in the genetic code of life ...
There are three principal classes of macronutrients: carbohydrate, protein and fat. [1] Macronutrients are defined as a class of chemical compounds which humans consume in relatively large quantities compared to vitamins and minerals which provide humans with energy. Fat has a food energy content of 38 kilojoules per gram (9 kilocalories per ...
Biomolecules include large macromolecules such as proteins, carbohydrates, lipids, and nucleic acids, as well as small molecules such as vitamins and hormones. A general name for this class of material is biological materials. Biomolecules are an important element of living organisms, those biomolecules are often endogenous, [2] produced within ...
The term nucleic acid is the overall name for DNA and RNA, members of a family of biopolymers, [13] and is a type of polynucleotide. Nucleic acids were named for their initial discovery within the nucleus, and for the presence of phosphate groups (related to phosphoric acid). [14] Although first discovered within the nucleus of eukaryotic cells ...
Serine (symbol Ser or S) [3][4] is an α- amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − NH+. 3 form under biological conditions), a carboxyl group (which is in the deprotonated − COO−. form under biological conditions), and a side chain consisting of a hydroxymethyl ...
Vitamin B 3 (niacin or nicotinic acid) Vitamin B 4 (adenine) Vitamin B 5 (pantothenic acid) Vitamin B 6 (pyridoxine or pyridoxamine) Vitamin B 12 (cobalamin) Vitamin C (ascorbic acid) Vitamin D (calciferol) Vitamin E (tocopherol) Vitamin F.
Life functions through the specialized chemistry of carbon and water, and builds largely upon four key families of chemicals: lipids for cell membranes, carbohydrates such as sugars, amino acids for protein metabolism, and nucleic acid DNA and RNA for the mechanisms of heredity. Any successful theory of abiogenesis must explain the origins and ...