Chemistry 9701 · AS & A Level · Nitrogen compounds

Nitrogen compounds — practice question

(a(i))[2]

Use the Data Booklet to sketch the structure of the tripeptide Ala-Ser-Gly, with all peptide bonds drawn in full.

(a(ii))[1]

Calculate the relative molecular mass, $M_r$, of Ala-Ser-Gly.

(b(i))[1]

Electrophoresis is a method for separating mixtures of amino acids and peptides. A sample containing the tripeptide Ala-Ser-Gly and its three constituent amino acids was run by electrophoresis in a buffer at $\text{pH }11$. Draw the structure of serine at $\text{pH }11$.

(b)

Electrophoresis is a method for separating mixtures of amino acids and peptides. A sample containing the tripeptide Ala-Ser-Gly and its three constituent amino acids was run by electrophoresis in a buffer at pH $11$.

(b(ii))[4]

Identify the components labelled F-I in the diagram above.

(b(iii))[3]

Suggest the identities of the species responsible for spot P and spot S. Explain your answers.

(c(i))[1]

State the reagents and conditions required to convert the tripeptide into its three constituent amino acids.

(c(ii))[1]

Name the reaction type in (i).

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: Accurate displayed structure of the tripeptide

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