(a)[3]
Collagen is the most abundant structural protein in vertebrates. It gives the skin flexibility and strength. Explain how the structure of a collagen fibre gives the skin strength.
(b)[2]
The enzyme collagenase breaks down collagen. Collagenase has several important medical uses, including treatment of burnt skin. Scientists investigated how pH affects the activity of collagenase at $37\,^{\circ}\text{C}$. The results of their investigation are shown in Fig. 6.1. Explain why the activity of collagenase is lower at $\text{pH }8.0$ than at the optimum pH.
(main)[2]
Explain why collagenase activity is lower at pH $8.0$ than at the optimum pH.