Homework Help
Homework Help
View Details
Assignment Help
Assignment Help
View Details
Online Tutoring
Online Tutoring
View Details
Home » Chemistry Homework Help » Biochemistry » Disaccharides
Disaccharides
These are the carbohydrates which give two units of monosaccharides on hydrolysis with dilute acids or enzymes. Some examples are:



This implies that a disaccharide is formed by condensation of two monosaccharides units. The two monosaccharide units in a disaccharide are joined together by an oxide (or ether) linkage formed by loss of a water molecule. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage.

Sucrose (cane-sugar), C12H22O11

Sucrose is the most widely occurring disaccharide. It is found in all photosyntheric plants. It is obtained commercially from sugarcane or sugarbeets. Its aqueous solution is dextrotatory with specific rotation + 66.5˚. On hydrolysis with dilute acids or enzyme invertase, 1 mole of sucrose gives 1 mole of D-(+)-glucose and 1 mole of (D)-(-)-fructose.



Sucrose is a non-reducing sugar. It indicates that the two hexones must have joined through a glycosidic linkage involving C- of -glucose and C-2 of -fructose. As a result, the reducing groups of glucose and fructose are involved in the formation of glycosidic linkage and hence sucrose behaves as a non-reducing sugar.

Haworth (1927) suggested the following structure of sucrose.

Maltose, C12H22O11

When starch is hydrolysed by the enzyme diastase, maltose is formed as one of the products.



On hydrolysis with dilute acids, one mole of maltose yields 2 moles of D-(+)-glucose.



Maltose is a reducing sugar. In maltose the two D-glucose units are linked through -glycosidic linkage between C-1 of one glucose unit and C-4 of the other. The free aldehyde group can be produced at C-1 of the second glucose in solution. Hence, maltose shows reducing properties.

Both the glucose units are in pyranose form. The structure of maltose is given below:

Lactose, (milk sugar), C12H22O11

Lactose is present in the milk and is also known as milk sugar. One hydrolysis with dilute acids one mole of lactose yields 1 mole of D-glucose and one mole of D-galactose



Lactose is a reducing sugar. In lactose, D-glucose and D-galactose units are linked through –glycosidic linkage between C-1 of galactose and C-4 of glucose unit.

Services:- Disaccharides Homework | Disaccharides Homework Help | Disaccharides Homework Help Services | Live Disaccharides Homework Help | Disaccharides Homework Tutors | Online Disaccharides Homework Help | Disaccharides Tutors | Online Disaccharides Tutors | Disaccharides Homework Services | Disaccharides

Submit Your Query ???
Topics
Nucleic Acid Functions Carbohydrates Glucose-Cyclic Structure Disaccharides Enzymes Fructose Functions Of Carbohydrates Glucose Hormones Enzyme Activity Mechanism Monosaccharides Nucleic Acids Polysaccharides Proteins, Amino Acids Proteins Structure The Cell Vitamins Biostatistics Mutarotation Monosaccharides Properties Compound Lipids Derived Lipids Fatty Acids Lipids Simple Lipids Radiation-Detection Measurement Synthetic Polymers Amino Acids Bioenergetics Biological Oxidation Reduction Cell Membrane Cell Motility, Cytoskeleton Cerebrospinal Fluid Chromatography Proteins Classification Clonal Selection Theory Blood Coagulation Coenzymes Nerve Impulse Conduction Connective Tissue DNA, RNA Diagnostic Applications Lipids-Digestion, Absorption Proteins-Digestion, Absorption Endoplasmic Reticulum Enzyme Inhibition Enzyme Linked Assay Enzymes Classification Erythrocytes Vitamins-Complex Group Extracellular Enzymes Fermentation, Putrefaction Fibrinolysis Folic Acid ATP Functions Bile Salts Functions Functions Of Blood Plasma Proteins Functions Gastric Juice Hemoglobin Blood Lacing Hemolysis Blood Clotting Inhibitors Intermediary Metabolism Enzymes Intracellular Location Leukocytes Lymph, Sweat, Synovial Fluid Histocompatibility Proteins-Transport Mechanism Metabolism Study Mitochondria Muscles Niacin Nucleoproteins Nucleotides Nucleus Oxidative Phosphorylation Oxyhemoglobin Pancreatic Juice Peptides Importance Proteins Properties Polyacrylamide Electrophoresis Amino Acids Properties DNA Properties Proteins Characterization Nucleotide Transhydrogenases Relaxation Riboflavin Saliva Nucleic Acids Structure Protein Molecule Structure Thiamine Transmission At The Synapse Transport Across Membranes Variations In Disease Vitamin A Vitamin B Vitamin C Vitamin D Vitamin E Vitamin K