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CIE Jun 2014 v3 Paper 4 Q6
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![14 Section B Answer all the questions in the spaces provided. PMT Proteins and deoxyribonucleic acid, DNA, are two important polymers that occur within living organisms. (a) Proteins have a number of levels of bonding: primary, secondary and tertiary. Complete the table to indicate the level of bonding responsible for the features described. feature level of bonding formation of -helix formation of disul de bonds formation of ionic bonds linking amino acids [3] (b) The diagram shows part of a DNA molecule. Study the diagram and give the correct names for the blocks labelled J, K, L and M. guanine adenine block letter name J K L M [4]UCLES 2014 9701/43/M/J/14<br />
PMT 15 (c) The DNA molecule is formed from two polymer strands which are held together until DNA replication occurs. (i) What type of bonding holds the strands together?(ii) Explain why this type of bonding allows the base pairs within the strands to separate during replication at normal body temperature.[2] (d) In the polymer RNA, the identities of two of the blocks, J, K, L or M, are different. For one of these blocks that are different, give its correct name in DNA and in RNA. DNA:RNA:[1] [Total: 10]UCLES 2014 9701/43/M/J/14 [Turn over<br />](https://learnah.org/wp-content/uploads/2018/08/June_2014_v3_QP_-_Paper_4_CIE_Chemistry_A-level_6-0.jpg)
![Page 7 Mark Scheme Syllabus Paper GCE A LEVELMay/June 2014 9701 43 (a) PMT feature level of bonding formation of -helix secondary formation of disulfide bonds tertiary formation of ionic bonds tertiary linking amino acids primary (b) block letter name Deoxyribose Cytosine Phosphate Thymine (c) (i) H/hydrogen (bonds between bases) (ii) Bonds are weak and so require relatively little energy to break / are easily broken (d) (sugar, J) (base, M) DNA deoxyribose RNA ribose thymine / T uracil / U (a) Expression: n = or equivalent 100 2.5 1.1 74 n = 3.1 hence G has three carbon atoms (b) (i) ( 1.1) RCH3 or RCH2R or methyl or CH3 [3] 4[1] [1] [1] [1] [Total: 10] [1] [1] ( 2.2) (R)CH2CO(R) or CH3CO(R) ( 11.8) (R)COOH or (R)CONH(R) 3[1]Cambridge International Examinations 2014<br />](https://learnah.org/wp-content/uploads/2018/08/June_2014_v3_MS_-_Paper_4_CIE_Chemistry_A-level_6.jpg)