Proteins
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Explain the Four levels of structure of proteins and their significance

a)     Primary

i)        Nature

(1)  Linear sequence of amino acids with peptide linkages

ii)      Significance

(1)  Chances in sequence may have overall effect on structure and activity

(2)  Almost infinite number of sequences

b)     Secondary

i)        Nature

(1)The formation of the alpha-helix and beta-pleated sheets, held together by hydrogen bonds.

ii)      Significance

(1)  ?

c)     Tertiary

i)        Nature

(1)  a complex structure, usually globular, resulting from further folding of the secondary structure of protein

(2)  forms spontaneously due to attractions and repulsions among amino acids with different charges on their R groups.

(3)  Active sites possible,added strength due to Ionic bonds, disulphide linkages, and possibly prosthetic groups and coenzymes.

d)     Quaternary

i)        the overall structure of a globular protein molecule that consists of two or more polypeptide chains.

ii)      Most large, non-structural proteins have more than one polypeptide and this leads to a greater range of biological activity.

Outline the difference between Fibrous and Globular proteins, with reference to two examples of each type

Explain the significance of Polar / Non Polar Amino Acids