a. A polypeptide is said to have direction. How are the two ends of the chain described?

b. What type of chemical bonding is responsible for maintaining the primary structure of a protein?

c. What is meant by the term amino acid residue?

d. Draw a diagram to show how a hydrogen bond may be formed between two peptide bonds in a polypeptide chain.

e. List the different types of interaction responsible for stabilising the tertiary structure of a protein.

f. What is the major difference in the position of the hydrogen bonds in the secondary and tertiary structures of a protein?

g. i. Name the amino acid that gives rise to a disulfide bridge.

ii. What part do disulfide bridges play in stabilising the structure of a protein?