Disaccharides: Definition, Structure & Examples - Disaccharides are formed when two monosaccharide units covalently bond together through dehydration synthesis. A common example is sucrose, or table sugar.
When the process of dehydration synthesis covalently bonds two monosaccharides together, the result is a disaccharide. (Remember that saccharide means sugar. The prefix di- means two.) We are all aware of many disaccharides. Common table sugar, sucrose, is a disaccharide, composed of a molecule of glucose bonded to a molecule of fructose. Lactose, or milk sugar, is a disaccharide composed of glucose combined with the monosaccharide galactose. Oligosaccharides consist of two to ten monosaccharide units bonded together, and some types can cause very unique problems, such as the excessive gas and stomach distress you get when you eat beans. Beans contain large amounts of oligosaccharides.
Some adults lose the ability to digest the milk sugar lactose, because their bodies produce insufficient amounts of the enzyme lactase. Lactase is responsible for the hydrolysis of lactose to glucose and galactose. Individuals with this condition suffer from gas, diarrhea, and cramps after the ingestion of lactose. The condition is more prominent in blacks than in members of other races, compounding the difficulty of relief efforts in African countries suffering from famine due to years of drought. A major food supplement shipped to famine-stricken areas is dried milk, because it is light and easier to transport than other protein sources. However, because of enzyme deficiencies, the recipients of this aid do not always benefit as much as their benefactors intend. (Source: Avila, Vernon L. Biology : Investigating Life On Earth Jones and Bartlett/Bookmark Series in Biology Page 59)
Posting Komentar