DP Chemistry (last assessment 2024)

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Question 19N.3.hl.TZ0.10b(i)

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Date November 2019 Marks available [Maximum mark: 3] Reference code 19N.3.hl.TZ0.10b(i)
Level hl Paper 3 Time zone TZ0
Command term Describe Question number b(i) Adapted from N/A
b(i).
[Maximum mark: 3]
19N.3.hl.TZ0.10b(i)

Aspartame is formed from the two amino acids aspartic acid (Asp) and phenylalanine (Phe).

Chromatography is used in the analysis of proteins in the food and pharmaceutical industry.

(b(i))

Describe, using another method, how a mixture of four amino acids, alanine, arginine, glutamic acid and glycine, could be separated when placed in a buffer solution of pH 6.0.

[3]

Markscheme

Any three of:
«gel» electrophoresis «technique»
OR
mixture «in buffer solution» placed on gel/paper ✔

voltage/potential «difference» applied ✔

amino acids move differently «depending on pH/isoelectric point» ✔

compare/measure distances travelled/Rf values ✔

NOTE: Accept “mixture placed on plate covered with polyacrylamide «gel» OR “mixture put in a gel «medium»”.

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