3.1.2.1 Monosaccharide
A monosaccharide is a carbohydate that contains a single polyhydroxy aldehyde or polyhydroxy ketone unit. Monosachharides can not be hydrolyzed to simpler carbohydrates. They may be subdivided into trioses, tetroses, pentoses, hexoses or heptoses depending upon the number of carbon atoms they posses. Pentoses and hexoses are important simple sugars present in food.
Type of pentose
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Source
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Functions
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D-Ribose
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Nucleic acids
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Structural elements in nucleic acids and coenzymes, e.g. ATP, NAD, NADP,flavoprotein.
Ribose- phosphate is an inter mediates in pentose phosphate pathway.
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D-Ribulose
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Formed in metabolism
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Ribulose phosphate is an intermediate in pentose phosphate path way.
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D-Arabinose
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Gum arabic, plum and cherry gums.
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Constituent of glycoproteins
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D-Xylose
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Wood gums, proteoglycans, glycosaminoglycans
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Constituent of glycoproteins
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Type of Hexose
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Source
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Functions
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D-Glucose
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Fruit juices. Hydrolysis of starch, cane sugar maltose, and lactose.
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The free sugar of the body. The sugar carried by the blood, and the principal one used by the tissues.
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D-Fructose
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Fruit juices, Honey, Hydrolysis of cane sugar.
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It can be changed to glucose in the liver and thus used in the body.
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D-Galactose
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Hydrolysis of lactose.
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It can be changed to glucose in the liver and metabolized.
It is synthesized in the mammary gland to make the lactose of milk.
It is a constituent of glycolipid and glycoprotein.
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D-Mannose
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Hydrolysis of plant mannan(plant polysaccharides) and gums.
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It is a constituent of many glycoproteins.
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Last modified: Thursday, 10 November 2011, 6:01 AM