Question 19M.3.sl.TZ2.14b(ii)
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.sl.TZ2.14b(ii) |
| Level | sl | Paper | 3 | Time zone | TZ2 |
| Command term | Explain | Question number | b(ii) | Adapted from | N/A |
Medicines and drugs are tested for effectiveness and safety.
Explain why diamorphine (heroin) is more potent than morphine using section 37 of the data booklet.
[2]
morphine has «two» hydroxyl groups AND diamorphine has «two» ester/ethanoate/acetate groups
OR
molecule of diamorphine is less polar than morphine
OR
groups in morphine are replaced with less polar/non-polar groups in diamorphine [✔]
«less polar molecules» cross the blood–brain barrier faster/more easily
OR
diamorphine is more soluble in non-polar environment of CNS/central nervous system than morphine [✔]
Note: Accept “alcohol/hydroxy” for “hydroxyl” but not ”hydroxide”.
Accept “fats” for “lipid”.
Accept “heroin” for “diamorphine”.
This question was reasonably well answered with many students receiving at least one of the two marks.
