CARBOHYDRATES - KEY NOTES

Contain Elements: Carbon, Hydrogen and Oxygen.

Biological Importance…  
 Energy Source  Carbohydrates are principal respiratory substrates
 Structural Compounds  Cellulose (CW of all plant cells) & Lignin
 Storage Compounds  Plants, Starch (common plant storage never in animals) Animals. Glycogen (e.g. mammalian liver)

CLASSIFICATION: The basic sugar unit = the saccharide

 

MONOSACCHARIDES

Examples of Monosaccharides: Glucose, Ribose

General There are the building blocks of other important C/H’s

Monosaccharides are:

Reducing Sugar Properties (all monosaccharides are reducing sugars). M/S are capable of REDUCING benedicts solution. When this reduction occurs benedicts solution changes from blue to orange/red.

 

DISACCHARIDES

Examples of D/S: Maltose (Malt sugar), Lactose (milk sugar)

Maltose formed by CONDENSATION of 2 units of glucose, the bond is called a glycosidic bond.

Note: In the exam you could be given half of the reaction below and asked to fill in the other half - you wouldn't be asked to come up with it all off the top of your head

2 molecules of glucose

+

Undergo a condensation reaction to form…
    + H2O
Maltose and Water

General Summary of disaccharides

 

POLYSACCHARIDES

Examples of P/S: Starch, Glycogen, Cellulose

These are an important group of carbohydrates. Two main divisions:

General Properties of P/S

Structural P/S

In these polysaccharides the sugar unit residues present in long chain molecules of the polymer are straight, and cross-linkages between chains occur giving the material its strength.

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