Question

Draw a simple picture and label amylose, amylopectin, and glycogen. Describe the unique properties of each polysaccharide, and where these are found.

Answer 1

Carbohydrates are mainly divided into 4 groups, which are monosaccharides, disaccharides, oligosaccharides, and polysaccharides.

• Polysaccharides are high molecular weight carbohydrates
• Main types of polysaccharides are cellulose (fiber),starch and glycogen
• Polysaccharides contains 10 or more monosaccharides attached together
• Majority of carbohydrates occur in polysaccharide form
• Polysaccharides are polymers of glucose
• In plants carbohydrate is found in the form of amylose, amylopectin and cellulose and is stored in animals as glycogen

Cellulose:

• Most abundant carbohydrate
• Insoluble in water
• Soluble in organic solvents
• Have high tensile strength
• Is a crystalline solid and have a white powdery appearance

Starch

• Is a white amorphous powder
• It lacks sweetness
• It contains 2 polymers amylose and amylopectin
• Insoluble in water and alcohol at normal temperature
• Breaks down into fragments called dextrin on hydrolysis
• Partial hydrolysis of starch occurs with high temperature (boiling in water) under pressure

Glycogen:

• Is the main storage form of polysaccharides in animal cells
• Is a polymer linked subunit of glucose
• Is extensively branched compared to starch
• Is compact than starch
• Is more soluble in water compared to starch

Polysaccharide rich foods are cereals, corn, roots like potato, present in small amounts in unripe fruits,

Vegetables, fruits and pulses contains polysaccharides other than starch

Sources:

Amylose and amylopectin are found in wheat, rice, cereals and grains

Glycogen is found in liver and muscles

Cellulose is present mainly in plant fibers, green leafy vegetables, bran, celery