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Lactose is a disaccharide foond in milk. It consists o a molecule o D-galactose an a molecule o D-glucose bondit bi beta-1-4 glycosidic linkage. It haes a formula o C12H22O11.

A carbohydrate is an organic compound comprisin anly carbon, hydrogen, an oxygen, uisually wi a hydrogen:oxygen atom ratio o 2:1 (as in watter); in ither wirds, wi the empirical formula Cm(H2O)n (whaur m coud be different frae n).[1] Some exceptions exist; for example, deoxyribose, a succar component o DNA,[2] haes the empirical formula C5H10O4.[3] Carbohydrates are technically hydrates o carbon;[4] structurally it is mair accurate tae view them as polyhydroxy aldehydes an ketones.[5]

The term is maist common in biochemistry, whaur it is a synonym o saccharide. The carbohydrates (saccharides) are dividit intae fower chemical groupings: monosaccharides, disaccharides, oligosaccharides, an polysaccharides. In general, the monosaccharides an disaccharides, which are smawer (lawer molecular wicht) carbohydrates, are commonly referred tae as succars.[6] The wird saccharide comes frae the Greek wird σάκχαρον (sákkharon), meanin "succar." While the scienteefic nomenclatur o carbohydrates is complex, the names o the monosaccharides an disaccharides very eften end in the suffix -ose. For example, grape succar is the monosaccharide glucose, cane succar is the disaccharide sucrose, and milk succar is the disaccharide lactose (see illustration).

Carbohydrates perform numerous roles in livin organisms. Polysaccharides serve for the storage o energy (e.g., starch an glycogen), an as structural components (e.g., cellulose in plants an chitin in arthropods). The 5-carbon monosaccharide ribose is an important component o coenzymes (e.g., ATP, FAD, an NAD) an the backbone o the genetic molecule kent as RNA. The relatit deoxyribose is a component o DNA. Saccharides an thair derivatives include mony ither important biomolecules that play key roles in the immune seestem, fertilization, preventin pathogenesis, bluid clottin, an development.[7]

In fuid science an in mony informal contexts, the term carbohydrate eften means ony fuid that is parteecularly rich in the complex carbohydrate starch (sic as cereals, breid, an pasta) or semple carbohydrates, sic as succar (foond in candy, jams, an desserts).

References[eedit | eedit soorce]

  1. Western Kentucky University (May 29, 2013). "WKU BIO 113 Carbohydrates".
  2. Eldra Pearl Solomon, Linda R. Berg, Diana W. Martin; Cengage Learning (2004). Biology. p. 52. ISBN 978-0534278281.CS1 maint: multiple names: authors leet (link)
  3. National Institute of Standards and Technology (2011). "Material Measurement Library D-erythro-Pentose, 2-deoxy-".
  4. Long Island University (May 29, 2013). "The Chemistry of Carbohydrates" (PDF).
  5. Purdue University (May 29, 2013). "Carbohydrates: The Monosaccharides".
  6. Flitsch, Sabine L.; Ulijn, Rein V (2003). "Succars tied to the spot". Nature. 421 (6920): 219–20. doi:10.1038/421219a. PMID 12529622.
  7. Maton, Anthea (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. pp. 52–59. ISBN 0-13-981176-1. Unknown parameter |coauthors= ignored (|author= suggested) (help)

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