EXPORT CITATION

Chapter-04 Carbohydrates–I: Chemistry, Digestion and Absorption of Carbohydrates

BOOK TITLE: Textbook of Biochemistry for Dental Students

Author
1. Vasudevan DM
2. S Sreekumari
3. Vaidyanathan Kannan
ISBN
9789350254882
DOI
10.5005/jp/books/11333_4
Edition
2/e
Publishing Year
2011
Pages
11
Author Affiliations
1. Faculty of Medicine, Amrita Vishwa Vidyapeetham, (Amrita University), Kochi, Kerala, Formerly Principal, College of Medicine, Amrita, Kerala; Formerly, Dean, Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, Amrita Vishwa Vidyapeetham (Deemed University), Cochin, Kerala, E-mail: dmvasudevan@aims.amrita.edu, PG Programs and Research College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India, College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India; Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, India
2. Jubilee Mission Medical College, Trissur, Kerala, Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India, Government Medical College, Thrissur and Thiruvananthapuram, Kerala, India; Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India; Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
3. Amrita Institute of Medical Sciences, Kochi, Kerala, India, Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla, Kerala, India, Believers Church Medical College and Hospital, Thiruvalla, Kerala, India
Chapter keywords

Abstract

Carbohydrates are polyhydroxy aldehydes or ketones or compounds, which yield them on hydrolysis. Carbohydrates are classified into Monosaccharides, Disaccharides and Polysaccharides, based on the number of sugar/saccharide units they possess. Common examples of monosaccharides include Glucose, Fructose, Galactose, and Mannose. Important examples of disaccharides are Sucrose, Lactose and Maltose. Monosaccharides exhibit stereoisomerism, optical isomerism and anomerism. The penultimate carbon atom is the reference carbon for naming mirror images. The stereoisomers are prefixed as ‘D’ or ‘L’. D sugars are naturally occurring. Anomers of monosaccharides are produced by the spatial configuration with reference to the first carbon atom in aldoses and the second carbon atom in ketoses. Two anomers of Glucose are alpha-D glucose and beta-D glucose. Mutarotation is the result of anomerism. All reducing sugars form characteristic osazone crystals. Glucose and fructose form needle-shaped crystals. Maltose forms sun flower shaped crystals. Lactose forms hedgehog shaped crystals. Sucrose is formed from glucose and fructose. Lactose is formed from galactose and glucose. Maltose is formed from two glucose molecules. Mucopolysaccharides or glycosaminoglycans (GAG’s) such as hyaluronic acid, chondroitin sulfate and keratan sulfate are associated with connective tissue. Keratan sulfate is the only GAG that does not contain uronic acid. Special glucose transporters perform the function of absorption of glucose in various cells. Absorption of glucose from intestinal lumen into intestinal cell is by sodium dependent glucose transporter (SGluT). Intestinal cells release glucose into blood stream by the carrier mechanism called glucose transporter type 2 (GluT2). The GluT4 has been implicated in Type 2 diabetes mellitus.

© 2019 Jaypee Brothers Medical Publishers (P) LTD.   |   All Rights Reserved