EXPERIMENT 3A:
CARBOHYDRATES: PREPARATION OF GLYCOGEN
OBJECTIVES
To isolate glycogen from natural sources using precipitation method.
INSTRUCTIONS
Prepare the following materials (take out the raw meat from the shells and osterize in a blender) BEFORE coming to class:
Group 1: Oysters (talaba) Group 4: Oysters (talaba)
Group 2: Green mussels (tahong) Group 5: Green mussels (tahong)
Group 3: Clams (tulya) Group 6: Clams (tulya)
Refrigerate your glycogen preparation. Do not leave it in your lockers. Use it on the day it is prepared.
INTRODUCTION
Carbohydrates are polyhydroxy aldehydes or ketones and their derivative, and are therefore termed aldoses or ketoses accordingly. Carbohydrates that are water soluble and sweet to taste are called sugars. They are classified into monosaccharides or simple sugars containing a saccharide group which cannot be hydrolyzed further; oligosaccharides consist of 2-10 saccharide group linked by acetal or ketal linkages. Oligosaccharides can be hydrolyzed to their respective monosaccharides or to two molecules of simple sugars called disaccharides. Polysaccharides, which contain monosaccharide residues in glucosidic linkage, may be large linear or branched molecules. Homopolysaccharides yield only one kind of monosaccharide upon hydrolysis, such as starch and glycogen, while heteropolysaccharides upon hydrolysis yield a mixture of monosaccharides and derived products. Polysaccharides with structural functions are cellulose and agar-agar. There are polysaccharides associated with energy storage (nutrient or storage polysaccharides), examples are dextrin, glycogen, inulin and starch.
REAGENTS
95% alcohol
SAMPLES
Assigned shellfish
MATERIALS
Filter paper (clean cheesecloth may be used to remove the bigger particles)
Top loading balance
PROCEDURE
Weigh about 50 g of the osterized shellfish using a top loading or triple beam balance. Place in a beaker and add 100 mL of water. Heat...