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The role of carbohydrates

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19th October 2002 Chris Anthony The role of carbohydrates Carbohydrates contain 3 elements, Carbon (C), Hydrogen (H) and Oxygen (O), at a ratio of 1:2:1. Carbohydrates are found in three main forms, monosaccharides, disaccharides, and polysaccharides. Carbohydrates supply the body with the energy it needs to function. They are found almost exclusively in plant foods, such as fruits, vegetables, peas, and beans. Milk and milk products are the only foods derived from animals that contain a significant amount of carbohydrates. Carbohydrates are divided into two groups, simple carbohydrates and complex carbohydrates. Simple carbohydrates, sometimes called simple sugars, include fructose (fruit sugar), sucrose (table sugar), and lactose (milk sugar), as well as several other sugars. ...read more.


Glucose is used to make disaccharides and polysaccharides (polymer). Disaccharides are formed when two monosaccharides are condensed together. One monosaccharide loses an H atom from carbon atom number 1 and the other loses an OH group from carbon 4 to form the bond.The reaction, which is called a condensation reaction, involves the loss of water (H2O) and the formation of a 1,4-glycosidic bond. The reverse of this reaction, the formation of two monosaccharides from one disaccharide, is called a hydrolysis reaction and requires one water molecule to supply the H and OH to the sugars formed. Some examples of disaccharide are Sucrose (Glucose + Fructose), Lactose (Glucose + Galactose), and Maltose (Glucose + Glucose). ...read more.


Cellulose is a polmer of Beta Glucose, joined with (1-4) links. Its molecules do not curl up, but form long straight chains. These chains tend to lie parallel to each other, forming a bundle of molecules called a microfibril. They are very insoluble, and difficult to digest, because few organisms make an enzyme that can break the Beta (1-4) linkages. The main functions of carbohydrates as a whole are: 1. Substrate for respiration (glucose is essential for cardiac tissues) 2. Intermediate in respiration (e.g. glyceraldehydes) 3. Energy stores (e.g. starch, glycogen) 4. Structural (e.g. cellulose, chitin in arthropod exoskeletons and fungal walls) 5. Transport (e.g. sucrose is transported in the phloem of a plant) 6. Recognition of molecules outside a cell (e.g. attached to proteins or lipids on cell surface membrane). ...read more.

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