Sugars 1A -2

Monosaccharaides

Carbohydrates contain the elements C, H and O. They are often polymers (made up of the same repeating monomer). These monomers are called monosaccharaides; examples of these are glucose, fructose and galactose. Monosaccharaides have the same number of C as O and are often in the formula (CH2O)n.

There are two forms of glucose. They have the same chemical formula just different structural formula. 

The two types of glucose

Disaccharides

Disaccharides are formed when two monosaccharaides join together. They are formed by a condensation reaction (the removal of a water molecule) and they form a glycosidic bond (it is important to remember that disaccharides have glycosidic bonds between the two monosaccharaides. Examples of disaccharides are maltose (two alpha glucose molecules), sucrose (fructose and beta glucose) and lactose (galactose and alpha glucose).

Maltose forming between two alpha glucose molecules

Sucrose forming between a beta glucose and a fructose molecule

Lactose forming between an alpha glucose and a galactose molecule

Molecules - 1A-1

Monomers and polymers

Polymers are large complex molecules made up of repeating monomers.

A monomer is a small basic unit which can form with other monomers to make polymers.

Carbohydrates, proteins and nucleic acids are all examples of polymers.

Making polymers

Polymers are produced by a condensation reaction, this is when a water molecule is removed and therefore it links two monomers with a chemical bond between them.

Breaking down polymers

Polymers are broken down by a hydrolysis reaction, this is when a water molecule is added and it breaks the bond which held the two monomers together.

Example of a condensation/hydrolysis reaction

Enzyme Inhibitors 1A-6

Enzyme activity can be prevented by inhibitors. The two types of inhibitors are competitive and non- competitive.

A competitive inhibitor bears a similar shape to that of the substrate, therefore it can compete with the substrate t bind to the active site of the enzyme. If an inhibitor binds to an enzymes active site before the substrate does, the substrate cannot bind to that particular active site as it has been blocked. If there is a high concentration of inhibitors, the inhibitors will take up almost all of the active sites, leaving non for the substrates. However, if there is a high amount of substrate then the chances of the substrate binding to an active site before the inhibitor does are increased. 

Non-competitive inhibitors bind to the enzyme away from the active site. This changes the shape of the active site and therefore substrates can no longer fit. Unlike w

ith competitive inhibitors, increasing the concentration of substrates will not make much of a difference as they are not both competing for the active site.

The graph shows how increasing the amount of subtrate concentration would affect the rate of reaction for both types of inhibitors.