CIE Jun 2014 v3 Paper 4 Q8

Answers available below

PMT (a) Many common drugs are taken orally, but some medications, such as those based on protein molecules, are injected to prevent them being broken down in the digestive system. 18 (i) Name a functional group present in drug molecules that might be broken down by acid in the stomach.(ii) State the type of reaction that would cause such a breakdown.(iii) Which one of the following compounds would not be suitable to be taken orally? OH OH CH3 HO CH3 H3C OCH3 CH3O OCH3 HO CH3 N CH3 compound(iv) On the structure of your chosen compound in (iii), circle all the functional groups that might be broken down by acid. [5]UCLES 2014 9701/43/M/J/14<br /> 19 (b) One way of protecting drug molecules that are taken orally is to enclose them in liposomes. These are arti cially created spheres made from phospholipids which have an ionic phosphate head and two hydrocarbon tails. PMT Q R phospholipid liposome (i) State and explain in which location, P, Q or R, a hydrophobic drug could be carried.(ii) By considering the nature of the functional groups in A, B and C, explain why these drugs can be carried at position R in the liposome.[2] (c) Another method of protecting drug molecules is to trap them inside gold nano-cages. When they reach the site where they are needed, such as a tumour, the drug is released by exposing the site to infra-red radiation. (i) Suggest the size of the nano-cages in metres.(ii) Suggest why infra-red, rather than higher frequency radiation is used.[2] [Total: 9]UCLES 2014 9701/43/M/J/14 [Turn over<br />

Show answer