protein structure

Question 1

what is the primary structure of proteins

Answer 1

• linear sequence of amino acids which are held in peptide bonds
• read in triplet codes
• a single change in the base can cause diseases

Question 2

what is the secondary structure of proteins

Answer 2

• folding occurs to form the backbone of the protein
• there are four types of secondary stcruteures
• alpha - helix = it has a dipole moment, it is spiralled, it has a 3,6 residual turn point, the residual groups are extended radially (from the centre) of the structure
• beta - pleated sheets = the chains are fully extended, pleated, the side chains project above and below the backbone, they are stabilised by hydrogen bonds. there are two types PARALLEL, ANTIPARALLEL- this is more stable
• beta turns = reverse the direction of the polypeptide chain. to be a beta turn there needs to be the residual group of either GLYCINE and PROLINE
• loops= varies lengths, irregular shapes, flexible, they connect other elements at secondary structure

Question 3

what is super secondary structure

Answer 3

• this is when there is a mixture of a few different secondary structures

Question 4

what is tertiary structure

Answer 4

• 3d structure of protein molecule
• stabilised by hydrogen, disulfide, ionic, van dear waals bonds

Question 5

what is quaternary structure

Answer 5

• spatial arrangement of subunits in a protein composed of more than one polypeptide chain
• ecah sub unit can either be identical or different