Carbohydrates

Hexose Monosaccharides:

• Glucose
• Fructose
• Galactose

Pentose Monosaccharides:

• Ribose
• Deoxyribose

Disaccharides:

• Sucrose
• Lactose
• Maltose

Polysaccharides:

• Cellulose
• Starch
• Glycogen

Disaccharides:

• Sucrose
• Lactose
• Maltose

Polysaccharides:

• Cellulose
• Starch 
• Glycogen

YYY

Condensation is bond making and hydrolysis is bond breaking.

• When a glycosidic bond is formed, a water molecule is also formed.

What are disaccharides made from?

• Sucrose -------> Glucose + Fructose (broken down by sucrase)
• Lactose --------> Glucose + Galactose (broken down by lactase)
• Maltose -------> Alpha Glucose + Alpha Glucose
• Cellobiose -------> Beta Glucose + Beta Glucose

• Made up of amino acids, of which there are 20.
• Diagram of amino acids:

• Cysteine makes disulphide bonds as it contains a sulphur.
• Bond between amino acids = peptide bond

R Groups:

• Different sizes
• Different atoms within each R Group
• Can be polar (charged) or non-polar

If the structure isn't right, it is more difficult to carry out the function.

How are protein molecules structured?:

• Shape is largely determined by R Group interaction, if the R Groups share the same charge, they will repel each other, if they are oppositely chagred they will attract each other.

• Primary Structure: A linear chain of amino acids.
• Secondary Structure: Chain becomes either alpha helix (maintained by hydrogen bonds) or a beta pleated sheet (maintained by hydrogen bonds)
• Tertiary Structure: Vital the the function of the protein, eg a hormone must be able to fit into a hormone receptor and an enzyme must have an active site that is complementary to the substrate.
• Quaternary Structure: When a number of polypeptide chains are fitted together, eg haemoglobin.

Starch: Add iodine solution, if starch is present, it will become black.

Reducing Sugars: Perform the Benedict's test, add Benedict's solution and heat until water boils, this should produce a brick red precipitate.

Non-Reducing Sugars: Add a small amount of acid and then bring to the boil in a water bath, then allow to cool and add alkali to neutralise, add benedict's solution and heat again in a water bath, the resulting precipitate should be brick-red if positive.

Lipids: Add ethanol to substance subject to testing and add this into water column, if results are positive, the water will become cloudy/milky. (This is the emulsion test)

Proteins: Add drops of Biuret Solution to the sample, stirring gently at the same time, if results are positive it will turn purple/violet.