DP Biology (first assessment 2025)
Question 19M.2.SL.TZ2.b
Date | May 2019 | Marks available | [Maximum mark: 3] | Reference code | 19M.2.SL.TZ2.b |
Level | SL | Paper | 2 | Time zone | TZ2 |
Command term | Draw | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 3]
19M.2.SL.TZ2.b
Draw the structure of a dipeptide.
[3]
Markscheme
a. two amino acids, one with NH2/NH3+end and one with COOH/COO– end ✔
b. peptide bond between C=0 and N—H correctly drawn ✔
c. «chiral» C with H and R group on each amino acid ✔
d. peptide bond labelled/clearly indicated between C terminal of one amino acid and N terminal of the second amino acid ✔
Labels not required for amino group and carboxyl group.
Examiners report
Structure of the dipeptide – candidates who also do chemistry were at an advantage here. Diagrams went from the superb to something Picasso might have produced.
