CIE Jun 2015 v3 Paper 4 Q9

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16 (a) DNAngerprinting has become a very important technique for analysing samples from living or once-living organisms. (i) After extraction and puri cation, what is therst step in analysing a sample of DNA?[1] (ii) What can be done to increase the amount of DNA for analysis?[1] (iii) During electrophoresis, it is observed that amino acids can move in different directions or not at all, whilst DNA fragments always move in the same direction. Explain these two observations.[2] (iv) DNAngerprinting can also be useful in archaeology. Which of the following would not be suitable for analysis by DNAngerprinting? Put a cross (x) in the appropriate box(es). a piece of leather from an Egyptian tomb a sample of skin from a mummi ed body a fragment of ancient pottery a piece of wood from a Roman chariot [1] (b) (i) X-ray crystallography can be used to help analyse the structure of macromolecules. What does this technique tell us about a particular macromolecule?[1]UCLES 2015 9701/43/M/J/15<br /> 17 (ii) Which element will show up most strongly in the X-ray crystallography of a biological polymer of general formula CvHwPxNyOz? Explain your answer.[1] (c) (i) Explain what is meant by a partition coef cient.[1] (ii) The partition coef cient of a particular pesticide between hexane and water is 6.0. A solution contains 0.0042 g of the pesticide dissolved in 25 cm3 of water. The solution is shaken with 25 cm3 of hexane. Calculate the mass of pesticide that will be dissolved in the hexane layer at equilibrium.UCLES 2015 9701/43/M/J/15 [2] [Total: 10] [Turn over<br />

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