Monosaccharides Carbohydrates that cannot polysaccharides

Carbohydrates are polyhydroxy aldehydes, polyhydroxy ketones, or compounds that can be hydrolyzed to them. A carbohydrate that cannot be hydrolyzed to simpler compounds is called a monosaccharide. A carbohydrate that can be hydrolyzed to two monosaccharide molecules is called a disaccharide. A carbohydrate that can be hydrolyzed to many monosaccharide molecules is called a polysaccharide. 

Carbohydrates are classified based upon the products formed when they are hydrolyzed. Monosaccharides are simple sugars that cannot be broken down into simpler sugars upon hydrolysis. Examples of monosaccharides are glucose, ribose, deoxyribose, and fructose. Disaccharides contain two monosaccharide units and yield two monosaccharides upon hydrolysis. Examples of disaccharides are lactose, maltose, and sucrose. Polysaccharides are polymers of monosaccharide units and yield many individual monosaccharides upon hydrolysis. Examples of polysaccharides are starch, glycogen, and cellulose. 

The simplest carbohydrate, called a monosaccharide, is composed of a structure that cannot be hydrolyzed to simpler polyhydroxylic compounds. A disaccharide is a carbohydrate that contains two of these basic units, and a polysaccharide contains many polyhydroxylic monomers. 

Carbohydrates are divided into groups depending on how many monomers are combined by condensation polymerization monosaccharides (Latin saccharum, sugar ), disaccharides, trisaccharides (etc.), and polysaccharides. Monosaccharides are simple sugars that cannot be broken down into smaller carbohydrate units by acid hydrolysis. In contrast, hydrolysis of a disaccharide or trisaccharide yields two or three monosaccharides (either the same or different), while complete hydrolysis of a polysaccharide produces many monosaccharides (sometimes thousands of them). 

The simplest carbohydrates, those that cannot be hydrolyzed into simpler carbohydrates, are called monosaccharides. On a molecular basis, carbohydrates that undergo hydrolysis to produce only 2 molecules of monosaccharide are called disaccharides those that yield 3 molecules of monosaccharide are called trisaccharides and so on. (Carbohydrates that hydrolyze to yield 2-10 molecules of monosaccharide are sometimes called oligosaccharides.) Carbohydrates that yield a large number of molecules of monosaccharides (>10) are known as polysaccharides. 

Quantitative precipitin tests were performed as described.73 The amounts of precipitates obtained at the various concentrations were measured by the protein phenol method.74 The inhibition values are recorded in Table I. These inhibition data show that the precipitin reaction between the tetrahet-eropolysaccharide and the anti-GlcA antibodies is strongly inhibited by d-glucuronic acid, but with the exception of galacturonic acid none of the other carbohydrates were inhibitory. The data in the table also show that the carbohydrates tested did not inhibit the precipitin reaction between the polysaccharide and anti-GlcA-Rha antibodies. The monosaccharides alone cannot completely fit the active site of this antibody to give a precipitin test. 

---