| Date | May 2018 | Marks available | 2 | Reference code | 18M.3.sl.TZ2.15 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Distinguish | Question number | 15 | Adapted from | N/A |
Question
Drug testing is necessary to determine safe and effective doses.
Distinguish between the lethal dose (LD50) and the toxic dose (TD50).
Markscheme
LD50: amount/dose that kills 50% of the population
TD50: amount/dose that negatively affects/produces toxic effects in 50% of the population
Award [1 max] for “LD50 used in animal trials AND TD50 used in human studies”.
[2 marks]
Examiners report
[N/A]
