Concept 5.2 Summary

Carbohydrate-an organic compound made up of sugar molecules (containing carbon, hydrogen and oxygen in the ratio of 1:2:1).
-most of carbohydrates are hydrophilic

Different Types of Sugar:
1. Monosaccharides-simple sugars containing just one sugar unit.
examples: glucose, fructose, galactose (sugar names end in the suffix -ose)

2. Disaccharides-made up by two monosaccharides (double sugar).
-formed by the dehydration reaction.
example: sucrose
*Sucrose consists of one glucose molecule and a fructose molecule linked together.

3. Polysaccharide-a long polymer chain made up of simple sugar monomers (complex charbohydrates)

Examples of polysaccharides:
1. starch-found in plant cells
-a chain of many glucose monomers
* The stored glucose in the starch molecules become available when those molecules are broken down or digested.
2. glycogen-a chain of many glucose monomers
-more highly branched than a starch polymer
-stored as granules in liver and muscle cells in humans (it breaks down to release energy when the body needs energy)
3. cellulose(also called fiber)-a chain of many glucose monomers
-multiple cellulose chains are linked together with hydrogen bonds
* Most animals (including humans) cannot digest cellulose because they lack the molecule necessary to break the bonds between the glucose monomers in cellulose. Therefore, it just passes through our digestive system, helps keeping it healthy, BUT, does not serve as a nutrient.

Concet Check 5.2
1. Explain the difference between a monosaccharide and a disaccharide. Give an example of each.
A monosaccharide is a simple sugar containing just one sugar unit. Example:glucose
A disaccharide is made up of two monosaccharides. Example:sucrose

2. Compare and contrast starch, glycogen, and cellulose.
Starch is mostly found in plants. A glycogen polymer is more highly branched than a starch polymer. A cellulose can't be digested in human and most of the animal bodies.

3. How do animals store excess glucose molecules?
The glucose molecules are stored in the form of a polysaccharide called glycogen. In humans, most glycogen is stored as granules in liverand muscle cells. When the body needs energy, itbreaks dwon these glycogen granules, releasing glucose.