1. POLYSACCHARIDES From Greek: Poly meaning many Sacchar meaning sugar
Are made from sugars

2. Carbohydrates/sugars:
Are the fuel and building blocks for life
Are building blocks (monomers) for polysaccharides
Examples monosaccharides:
Glucose
Fructose

3. Glucose
The most common monosaccharide, glucose – C6H12O6, is of central importance in the chemistry of life

4. Synthesis
Linking monosaccharides (sugars) together

5. Dehydration synthesis process:

6. Key Characteristics of Sugars
They are hydrocarbons with carbonyl groups (C=O) and multiple hydroxyl groups (OH)
Carbon skeletons are 3 to 7 carbons long.
Their names end in the suffix “ose”.

7. Ketose vs Aldose
If the carbonyl group is in the middle of the chain it is classified as a ketose, and if it is on the end of a chain as an aldose.

8. Small differences in structure can cause major differences in the behaviour and shape of the sugar

9. Galactose and glucose are optical isomers (same number and types of atoms, different properties).
Galactose is not very water-soluble therefore is not easily absorbed – is not digested

10. When in water (aqueous solution) most sugars form rings.
Example: Glucose
Chemical equilibrium between the linear and ring structure favors the ring structure.

11. Naming sugars: Prefixes of: Mono, di, tri, … poly
Mono is a single sugar
Di = two sugars joined
Tri = three sugars joined
Poly = many sugars joined

12. Aldose vs. Ketose (See earlier notes)
Depending on the size of a carbon skeleton (ranges from 3 – 7), monosaccharides are named as:
Trios – 3 carbon chain
Tetrose – 4 carbon chain
Pentose – 5 carbon chain
Hexose – 6 carbon chain
Heptose – 7 carbon chain
Aldose vs. Ketose (See earlier notes)

13. aldo- + tri + ose ------> aldotriose
Forming name:
 (keto-/aldo-) + (# of carbons) + -ose
Examples
a monosaccharide that contains an aldehyde and three carbons is formed in this way:
aldo- + tri + ose > aldotriose
a five carbon sugar that contains a ketone is called a ketopentose.

14. TASK
Worksheet questions 1 - 9