Elementary plant Biochemistry and Biotechnology (2+1)

Monosaccharide

Monosaccharides

Monosaccharides are the simplest form that cannot be hydrolyzed further into smaller units. They are classified into

1. Simple monosaccharides
2. Derived monosaccharides

Based on the type of functional group and

• The number of carbon atoms they possess
• Derived monosaccharides include the derivatives of simple monosaccharides such as oxidation products, reduction products, substitution products and esters

Classification of monosaccharides

Monosacchar ides	No. of carbon atoms	Aldose	Ketose	Occurrence
Simple
Triose	3	D-Glycerose	Dihydroxy acetone	Intermediary meta- bolites in glucose metabolism
Tetrose	4	D-Erythrose	D-Erythrulose
Pentose	5	D-Ribose	D-Ribulose	Ribose is a constituent of nucleic acid
		L-Arabinose	-	Occurs in oligosac- charides
		D-Xylose	D-Xylulose	Gum arabic, cherry gums, wood gums, proteoglycans
Hexose	6	D-Glucose	D-Fructose	Fruit juices and cane sugar
		D-Galactose	-	Lactose, constituent of lipids
		D-Mannose	-	Plant mannosans and glycoproteins
Heptose	7	-	D-Sedoheptulose	Intermediate in carbohydrate metabolism
Derived
Deoxysugar	5	2-Deoxyribose	-	DNA
	6	L-Rhamnose	-	Component of cell wall
Aminosugar	6	D-Glucosamine	-	A major component of polysaccharide found in insects and crustaceans (chitin)
Polyol	6	Sorbitol	-	Berries
	6	Mannitol	-	Commercially pre­pared from mannose and fructose
Aldonic acid	6	Gluconic acid	-	-
Uronic acid	6	Glucuronic acid	-	Constituent of chondroitin sulfate
	6	Galacturonic acid	-	Constituent of pectin
Aldaric acid (Saccharic acid)	6	Glucaric acid	-	Oxidation product of glucose
	6	Mucic acid	-	Oxidation product of galactose