AQA Specimen Paper 2 Q8

Answers available below

18 The anticancer drug cisplatin operates by reacting with the guanine in DNA. Figure 6 shows a small part of a single strand of DNA. Some lone pairs are shown. Figure 6 guanine 0 8 . 1 The DNA chain continues with bonds at X and Y. State the name of the sugar molecule that is attached to the bond at X. [1 mark] Barcode Typesetter code<br /> 0 8 19 . 2 Messenger RNA is synthesised in cells in order to transfer information from DNA. The bases in one strand of DNA pair up with the bases used to synthesise RNA. Figure 7 shows two bases used in RNA. Figure 7 Suggest which of the bases A and B forms a pair with guanine in Figure 6 when messenger RNA is synthesised. Explain how the base that you have chosen forms a base pair with guanine. [4 marks] Question 8 continues on the next page Barcode Typesetter code Turn over <br /> 20 . 3 0 8 Cisplatin works because one of the atoms on guanine can form a co-ordinate bond with platinum, replacing one of the ammonia or chloride ligands. Another atom on another guanine can also form a co-ordinate bond with the same platinum by replacing another ligand. On Figure 6, draw a ring round an atom in guanine that is likely to bond to platinum. [1 mark] . 4 0 8 An adverse effect of cisplatin is that it also prevents normal healthy cells from replicating. Suggest one way in which cisplatin can be administered so that this side effect is minimised. [1 mark] Barcode Typesetter code<br /> 21 Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Barcode Typesetter code Turn over <br />

Show answer