Answer: The monosaccharides that are correctly paired with their class are (A) fructose : hexose ketose, (C) glyceraldehyde : triose aldose and (F) dihydroxyacetone : triose ketose.
Explanation: Monosaccharides are classified into two: aldose and ketose. In open chain form, monosaccharides have unbranched chains in which all the carbon atoms are linked by single bonds, one of the carbon atoms is double bonded to an oxygen atom to form a carbonyl group and each carbon atom has a hydroxyl group. An aldose is a monosaccharide in which the carbonyl group is at the end of the carbon chain while a ketose is a monosaccharide in which the carbonyl group is at any other position. A triose is a sugar with three carbon atoms, sugars with four, five, six and seven carbon atoms are known as tetrose, pentose, hexose and heptose respectively.
Fructose is a hexose ketose, erythrulose is a tetrose ketose, glyceraldehyde is a triose aldose, erythrose is a tetrose aldose, ribose is a pentose aldose while dihydroxyacetone is a triose ketose.
