| Date | May 2011 | Marks available | 4 | Reference code | 11M.3.hl.TZ2.F2 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Compare | Question number | F2 | Adapted from | N/A |
Question
Compare the structures of the natural pigments, chlorophyll and heme B using Table 22 of the Data Booklet.
Markscheme
both contain planar heterocyclic unit/porphyrin;
conjugated double bonds (in cyclic system) / alkene (groups);
Chlorophyll:
only chlorophyll has magnesium/ester (groups)/R-group on C3/long hydrocarbon chain;
Examiners report
Most candidates could compare successfully the structures of chlorophyll and heme B.
