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5 marksStructure and Roles of Nucleic Acids

CAPE Biology Unit 1 · May/June 2021 · Paper 2 · Question 2(a)(i)

Figure 2 illustrates part of a DNA molecule composed of polynucleotide strands.

Provide labels on Figure 2 to identify the components labelled S, T, U, and V.

This question uses a figure or table from the paper — you'll see it when you practise.

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Other parts of this question

  1. 2(a)(ii)Draw a circle around a section of Figure 2 to identify a single nucleotide.[1 mark]
  2. 2(a)(iii)State how two nucleotides in a DNA molecule are held together.[1 mark]
  3. 2(a)(iv)Outline the roles of messenger RNA (mRNA) and transfer RNA (tRNA) in polypeptide synthesis in eukaryotic cells.[4 marks]
  4. 2(b)(i)Name the type of change in the gene that causes the production of abnormal haemoglobin in individuals with sickle-cell anaemia.[1 mark]
  5. 2(b)(ii)Outline how low oxygen saturation causes red blood cells to change into a sickle shape.[3 marks]
  6. 2(c)(i)Analyse the success of the gene therapy treatment for sickle-cell anaemia using the data presented in Figure 3.[3 marks]
  7. 2(c)(ii)Discuss three challenges that may limit the success of gene therapy as an effective medical treatment for diseases.[12 marks]

More practice: the rest of this paper · more Structure and Roles of Nucleic Acids questions · all CAPE Biology Unit 1 past papers