Question 18N.2.HL.TZ0.1
| Date | November 2018 | Marks available | [Maximum mark: 3] | Reference code | 18N.2.HL.TZ0.1 |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Deduce, State, Suggest | Question number | 1 | Adapted from | N/A |
Mutagens can be removed from the body by converting them to readily excreted metabolites. NNK is converted to a metabolite, NNAL-Gluc, which can be used as a biomarker for the uptake of NNK. Cotinine, a metabolite of nicotine, is an indicator of tobacco smoke uptake. The graph shows the relationship between these two metabolites in the urine of 233 smokers.
State the highest concentration of cotinine in the urine, giving the units.
[1]
42 nmol ml–1 ✔
Deduce, with a reason, whether the concentrations of cotinine and NNAL-Gluc would be higher in the urine or in the blood plasma of a smoker.
[1]
higher in urine due to concentration of waste products «during the process of urine production»
OR
higher in urine because water is reabsorbed «from glomerular filtrate/in the collecting duct»/ because «waste products» are not reabsorbed ✔
Suggest one advantage of using the urine concentration of cotinine rather than NNAL-Gluc to give a measure of the amount of tobacco smoke inhaled by a person.
[1]
higher «concentrations» so easier to measure/identify/find
OR
wider spread/greater range «of values/concentrations»
OR
units are larger/nmol rather than pmol ✔