1. What are "Langer's lines" and why are they important in surgery? [4 marks] 2. Discuss how the surface to volume ratio explains why there is a "minimum" possible size for mammals but a "maximum" possible size for insects. [4 marks] 3. Explain what is meant by each of the following terms: "stiffness", "tensile strength", "toughness" and "hardness". [4 marks] 4. Provide a definition of pH. Give the pH values of aqueous solutions that contain: i. 0.01 M HCl; ii. 0.001M NaOH; iii. 10 M HCl Give your answer to one decimal place in each case. [4 marks] 5. Name the type of functional groups in this molecule indicated by the arrows (1) and (2). Is the carbon atom (3) involved in aliphatic, anti-aromatic or aromatic bonding? Explain why. [4 marks] H3C CH3 N. ill OH OCH3 (3) OH OCH3 H CH3 (1) (2) 8. (a) What is the difference between a "thermoplastic" and a "thermoset" polymer? Give an example of a thermoset polymer and describe its properties. Which polymer is typically used as the material for the acetabular cup of a total hip replacements and why? [5 marks] (b) Burns are classified in three degrees according to their severity. Describe each of the degrees of burn. Describe the most common treatment for severe burns. What is the advantage of using skin tissue engineering over this treatment? [5 marks] (c) Explain what is meant by an "enzyme". [3 marks] (d) Describe the components of a typical enzyme. [2 marks] (e) Explain how an enzyme works and two ways in which the action of an enzyme can be inhibited. [5 marks] 9. (a) Describe the two types of metallic tooth-filling materials, and explain how they are used as tooth fillings. State one advantage and one disadvantage of using each type of metallic tooth-filling material [6 marks] (b) Explain what is meant by the term "carbohydrate" when applied to molecules. Give two examples of types of carbohydrate molecule. Which carbohydrate molecule is used in cellular respiration and what is this molecule converted into during cellular respiration? [4 marks] (c) Draw a sketch of a total hip replacement implant and label the three important parts of this device. [5 marks] (d) Explain what is meant by a "pH buffer". What exactly does a buffer achieve? Which molecule in blood acts as a buffer? [5 marks]