(a)[3]
Examine the table that outlines features of bonding in proteins. For each description of a bonding type, show whether it contributes to the primary, secondary or tertiary structure of a protein. The bonding types given are: disulfide bonds between parts of the chain; hydrogen bonds in a $\beta$-pleated sheet; ionic bonds between parts of the chain; peptide links between amino acids.
(b)[4]
Explain, using diagrams where suitable, how competitive inhibition of enzymes differs from non-competitive inhibition.
(c)[3]
The diagram shows one strand of DNA. Draw the matching strand, making the bonds joining the two strands clear and labelled. Name the bases in your strand, showing clearly which base pairs with each base in the strand shown.