Polysaccharides Lab Activity

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Polysaccharides Lab Activity

By | September 2010
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QUESTIONS

1. What are other sources of glycogen? Of starch?
a. Other sources of glycogen- Aside from the liver, it can also be found in skeletal muscles (for energy during strenuous exercise). It also occurs in tissues including adipose tissues, heart muscles, kidneys and the brain. It is also found in yeast, bacteria, fungi, molds and algae, oysters, and shellfish. b. Other sources of starch- Foods that are high in starch include breads, grains, cereals, pasta, rice, potatoes, peas, corn and beans – in other words, grains, legumes and some vegetables.

2. What are the end products of hydrolysis of glycogen? Of starch? * The end product of hydrolysis of both glycogen and starch is glucose (homopolysaccharides).

3. How do starch and glycogen differ structurally?
* Starch, a complex carbohydrate, is a polymer of glucose molecules. It occurs in two main forms: amylose and amylopectin

Characteristic| Amylose| Amylopectin|
Chain| Straight chain| Highly branched|
Linkage| 1-4 glycosidic linkage| Both 1-4 and 1-6 glycosidic linkage| % in Starch| 15-20%| 80-85%|
No. of Units| 300-500 monomer units| 25-30 glucose units| Molecular Mass| 300 000 amu| 50 000 amu|

* Glycogen is a polymer of glucose (up to 120,000 glucose residues) and is a primary carbohydrate storage form in animals. The polymer is composed of units of glucose linked alpha (1-4) with branches occurring alpha(1-6) approximately every 8-12 residues. The end of the molecule containing a free carbon number one on glucose is called a reducing end. The other ends are all called non-reducing ends. It is highly branched and it has a large molecular mass of 3 000 000 amu.

4. What is meant by achromatic point?
* It is the point at which starch no longer gives a positive result (blue color) to Iodine test.

5. Illustrate with equation how plants manufacture starch

6. Give another name for glycogen and another name for starch. *...

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