| Date | May 2018 | Marks available | 3 | Reference code | 18M.3.hl.TZ2.10 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Explain | Question number | 10 | Adapted from | N/A |
Question
Explain how the structure of vitamin A is important to vision using section 35 of the data booklet.
Markscheme
vitamin A oxidized to «11-cis-»retinal
extended conjugation
OR
extensive delocalization
cis-retinal converts to trans-retinal through absorption of light
Accept “vitamin A/hydroxyl/hydroxy/alcohol/CH2OH group oxidized to aldehyde/CHO «group in retinal»”.
[3 marks]
Examiners report
[N/A]
