CIE Nov 2015 v1 Paper 4 Q8

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14 Section B Answer all the questions in the spaces provided. PMT (a) The sequence of bases in DNA is a code for the order of amino acids in the primary structure of proteins. The diagram represents the stages involved in the formation of a protein from DNA. stage 1 stage 2 stage 3 ribosome protein DNA B1 B2 etc. (i) Identify the biochemical structures, A and B1, B2 etc. biochemical structure identity B1, B2 etc. (ii) Name the biochemical processes involved in stages 1 and 3. name of biochemical process process stage 1 stage 3 [2] [1]UCLES 2015 9701/41/O/N/15<br /> PMT (b) Adenine is an integral part of DNA. 15 NH2 N H adenine (i) State the molecular formula of adenine.[1] (ii) Identify the three other nitrogenous bases in DNA.[1] (iii) DNA has a double helical structure that consists of two strands linked together. What type of bonding exists between the phosphate and sugar groups within a DNA strand,different bases on the two strands?[2] (c) The breakdown of adenosine triphosphate, ATP, provides the energy for many cellular reactions. ATP + H2OADP + Pi What type of chemical reaction is this?[1] (d) X-ray crystallography can be useful in obtaining information about the structures of large organic molecules, such as ATP. The technique involves X-rays interacting with the electrons within the molecule. (i) Which element in the molecule of ATP will interact most strongly with the X-ray beam?[1] (ii) Explain why X-ray crystallography will not detect hydrogen atoms.[1]UCLES 2015 9701/41/O/N/15 [Total: 10] [Turn over<br />

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