2 Monosaccharides and Classification

Описание: Definition
Monosaccharides are the simplest form of carbohydrates.
They are polyhydroxy aldehydes or ketones and cannot be hydrolysed further into simpler carbohydrates.
Examples: Glucose, Fructose, Ribose
Classification of Monosaccharides
Monosaccharides are classified based on:
1. Number of carbon atoms 2. Type of functional group present
1. Classification Based on Number of Carbon Atoms
Monosaccharides are named according to the number of carbon atoms in their structure.
a) Trioses -3 Carbon Atoms
• Contain 3 carbons
• Examples:
o Glyceraldehyde
o Dihydroxyacetone

b) Tetroses -4 Carbon Atoms
• Contain 4 carbons
• Examples:
o Erythrose -Aldo Tetrose
o Erythrulose -Keto Tetrose

c) Pentoses -5 Carbon Atoms
• Contain 5 carbons
• Examples:
o Ribose -Aldo Pentoses
o Ribulose -keto Pentoses

d) Hexoses -6 Carbon Atoms
• Contain 6 carbons
• Most important group in human metabolism
• Examples:
o Glucose -aldohexose
o Fructose -ketohexose
e) Heptoses -7 Carbon Atoms
• Contain 7 carbons
• Example:
o Sedoheptulose -ketoheptose
o Glucoheptose aldoheptose
2. Classification Based on Functional Group
Monosaccharides are classified based on the type of carbonyl group present.
A. Aldoses
• Contain an aldehyde group (–CHO) at the terminal carbon (C-1)
• General structure: –CHO at one end
Examples of Aldoses: Glyceraldehyde, Erythrose, Glucose
B. Ketoses
• Contain a ketone group (C=O) usually at C-2 position
• Carbonyl group is present in the middle of the chain
Examples of Ketoses: Dihydroxyacetone, Ribulose, Fructose