Editing Carbohydrate (section)

==Disaccharides==
[[Image:sucrose 3Dprojection.png|thumb|[[Sucrose]], also known as table sugar, is a common disaccharide. It is composed of two monosaccharides: [[glucose|D-glucose]] (left) and [[fructose|D-fructose]] (right).]]
{{Main|Disaccharide}}
Two joined monosaccharides are called a [[disaccharide]], the simplest kind of polysaccharide. Examples include [[sucrose]] and [[lactose]]. They are composed of two monosaccharide units bound together by a [[covalent bond]] known as a [[glycosidic linkage]] formed via a [[dehydration reaction]], resulting in the loss of a [[hydrogen]] atom from one monosaccharide and a [[hydroxyl group]] from the other. The [[chemical formula|formula]] of unmodified disaccharides is C<sub>12</sub>H<sub>22</sub>O<sub>11</sub>. Although there are numerous kinds of disaccharides, a handful of disaccharides are particularly notable.

[[Sucrose]], pictured to the right, is the most abundant disaccharide, and the main form in which carbohydrates are transported in plants. It is composed of one [[glucose|D-glucose]] molecule and one [[fructose|D-fructose]] molecule. The [[systematic name]] for sucrose, ''O''-α-D-glucopyranosyl-(1→2)-D-fructofuranoside, indicates four things:
* Its monosaccharides: glucose and fructose
* Their ring types: glucose is a [[pyranose]] and fructose is a [[furanose]]
* How they are linked together: the oxygen on carbon number 1 (C1) of α-D-glucose is linked to the C2 of D-fructose.
* The ''-oside'' suffix indicates that the [[anomeric carbon]] of both monosaccharides participates in the glycosidic bond.

[[Lactose]], a disaccharide composed of one [[galactose|D-galactose]] molecule and one [[glucose|D-glucose]] molecule, occurs naturally in mammalian milk. The [[systematic name]] for lactose is ''O''-β-D-galactopyranosyl-(1→4)-D-glucopyranose. Other notable disaccharides include [[maltose]] (two D-glucoses linked α-1,4) and [[cellobiose]] (two D-glucoses linked β-1,4). Disaccharides can be classified into two types: reducing and non-reducing disaccharides. If the functional group is present in bonding with another sugar unit, it is called a reducing disaccharide or biose.