protein structure

Question 1

describe the primary structure of a protein

Answer 1

Appears like a simple string of beads. The sequence of amino acids in a polypeptide chain bonded together by peptide bonds

Question 2

describe the secondary structure of a protein

Answer 2

the primary structure can becomes coiled to form an alpha helix or a beta pleated sheet. These are held together by hydrogen bonds. These are relatively weak and can be broken by heat but collectively are strong.

Question 3

describe the tertiary structure of a protein

Answer 3

The secondary structure of the protein is further folded and is twisted to form a complex 3D structure. Held together by hydrogen, ionic and disulphide bonds.

Question 4

describe the quaternary structure of a protein

Answer 4

made up of 2 or more polypeptide chains, structure is maintained by the same bonds as tertiary. Some quaternary proteins have a prosthetic group which is additional. several polypeptide groups held together by bonds

Question 5

what are the 3 bonds in the tertiary structure and what is their role?

Answer 5

hydrogen: easily broken
ionic: formed between carboxyl and amine groups not used in the peptide bonds. Affected by pH
sulphide bonds/bridges: form when 2 amino acid cysteine molecules come close together and the sulphur atoms bond. These are strong

Question 6

what is a conjugated protein?

Answer 6

a protein that has a prosthetic group