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Amino acids, proteins and DNA (A-level only)

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Question 3

Which structure is predominant when aspartic acid is in an aqueous solution at pH 1\text{pH } 1pH 1?

A
H2N−CH−COO−∣H2C−COOH \begin{array}{ccc} \text{H}_2\text{N} & -\text{CH}- & \text{COO}^- \\ & | & \\ & \text{H}_2\text{C}-\text{COOH} & \end{array} H2​N​−CH−∣H2​C−COOH​COO−​
B
H3N+−CH−COOH∣H2C−COOH \begin{array}{ccc} \text{H}_3\text{N}^+ & -\text{CH}- & \text{COOH} \\ & | & \\ & \text{H}_2\text{C}-\text{COOH} & \end{array} H3​N+​−CH−∣H2​C−COOH​COOH​
C
H3N+−CH−COO−∣H2C−COOH \begin{array}{ccc} \text{H}_3\text{N}^+ & -\text{CH}- & \text{COO}^- \\ & | & \\ & \text{H}_2\text{C}-\text{COOH} & \end{array} H3​N+​−CH−∣H2​C−COOH​COO−​
D
H2N−CH−COO−∣H2C−COO− \begin{array}{ccc} \text{H}_2\text{N} & -\text{CH}- & \text{COO}^- \\ & | & \\ & \text{H}_2\text{C}-\text{COO}^- & \end{array} H2​N​−CH−∣H2​C−COO−​COO−​
Markscheme

Amino acids, proteins and DNA (A-level only) Questions

  1. A Level
  2. /Chemistry
  3. /Amino acids, proteins and DNA (A-level only)

30 exam-style questions on AQA A Level Chemistry Amino acids, proteins and DNA (A-level only), covering Amino acids (A-level only), Proteins (A-level only), Enzymes (A-level only), DNA (A-level only), and Action of anticancer drugs (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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