Amino acids: past paper questions

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• Question 9May/June 2026, paper 41Structured11 marksHas a diagram

  An amino acid is a compound that has both an amine group and a carboxyl group. The structures of three amino acids, P, Q and R, are shown in Figure 9.1.

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• Question 8Oct/Nov 2025, paper 42Structured16 marks

  Asparagine and aspartic acid are two naturally occurring amino acids. Their structures and isoelectric points are shown in Table 8.1.

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• Question 8Oct/Nov 2024, paper 42Structured12 marksHas a diagram

  The amino acid serine, ${\text{HOCH}}_2\text{CH}({\text{NH}}_2)\text{COOH}$, exists in two optically active forms. These optical isomers, isomer P and isomer Q, are shown in Fig. 8.1.

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• Question 7May/June 2023, paper 41Structured18 marksHas a diagram

  State the relative basicities of ethanamide, diethylamine and ethylamine in aqueous solution.

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• Question 7May/June 2026, paper 42Structured11 marksHas a diagram

  Alanine, ${\text{CH}}_3\text{CH}({\text{NH}}_2)\text{COOH}$, is an amino acid that contains a chiral centre. Different synthetic routes to produce alanine can lead to the formation of an optically active sample or a racemic mixture. Describe what is meant by optically active.

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• Question 9May/June 2025, paper 42Structured9 marksHas a diagram

  The structures of the amino acids serine and lysine are shown in Fig. 9.1. Draw the structure for the dipeptide, ser–lys, with molecular formula ${\mathrm{C}}_9{\mathrm{H}}_{19}{\mathrm{N}}_3{\mathrm{O}}_4$.

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• Question 8May/June 2024, paper 42Structured16 marksHas a diagram

  State the relative basicities of phenylamine, ${\text{C}}_6{\text{H}}_5{\text{NH}}_2$, benzylamine, ${\text{C}}_6{\text{H}}_5{\text{CH}}_2{\text{NH}}_2$, and ammonia, ${\text{NH}}_3$, in aqueous solution.

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• Question 8May/June 2024, paper 43Structured8 marksHas a diagram

  Neotame is an artificial sweetener added to some foods. State the number of chiral carbon atoms in a molecule of neotame.

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