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1 markAspects of Biochemistry

CAPE Biology Unit 1 · 2008 · Paper 2 · Question 1(a)(iii)

Carbohydrate molecules can be joined by alpha or beta linkages. Figure 1 shows two glucose molecules joined by an alpha-1-4 glycosidic linkage.

Distinguish between an 'α glycosidic linkage' and a 'β linkage'.

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Other parts of this question

  1. 1(a)(i)Using an α-1-6 linkage, attach a third glucose molecule in Figure 1.[2 marks]
  2. 1(a)(ii)Name ONE example of a carbohydrate that is made up of components with BOTH an α-1-4 glycosidic linkage and an α-1-6 linkage.[1 mark]
  3. 1(a)(iv)Comment on the difference in function between a carbohydrate with α linkages and a carbohydrate with β linkages.[2 marks]
  4. 1(b)(i)Describe the α helix bond in keratin.[2 marks]
  5. 1(b)(ii)Comment on TWO differences in physical properties of these proteins. Write your answer in the table below.[2 marks]
  6. 1(b)(iii)Identify the TWO bonds labelled A and B as shown in Figure 2.[2 marks]
  7. 1(c)Outline an experiment to determine experimentally the presence of catalase in chick peas.[3 marks]

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