DP Biology (last assessment 2024)
Question 17N.3.SL.TZ0.10b
| Date | November 2017 | Marks available | [Maximum mark: 1] | Reference code | 17N.3.SL.TZ0.10b |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 1]
17N.3.SL.TZ0.10b
Researchers in Korea set up an experiment to measure how accumulation of biofilm changes in water pipes under different conditions.
The graph shows the accumulation of biofilm in steel pipes when the water was untreated, treated with chlorine and filtered through a membrane.
[Source: adapted from Yoonjin Lee, (2013), Journal of Environmental Research Public Health 2013, 10 (9), pages 4143 – 4160]
(b)
Suggest why membrane filtration may be more suitable than chlorination in purifying the water.
[1]
Markscheme
a. does not affect taste of water/no chemicals added
b. lower biofilm accumulation over time
[Max 1 Mark]
