DP Biology (last assessment 2024)
Question 19M.3.SL.TZ2.b
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.SL.TZ2.b |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 1]
19M.3.SL.TZ2.b
The diagram shows the formation of a biofilm in a mammary gland, producing a mastitis infection.
[Source: © International Baccalaureate Organization 2019]
Suggest one reason, other than quorum sensing, for the resistance to antibiotics of a biofilm.
[1]
Markscheme
a. polysaccharide matrix/EPS does not let antibiotic pass/limits transport of antibiotic ✔
b. reduced metabolic activity/growth rate of bacteria in biofilm contributes to resistance ✔
c. increased cell density limits transport of antibiotic «to the interior of biofilm» ✔
d. «horizontal» transfer of antibiotic resistance via plasmids ✔
OWTTE
Examiners report
This question, about biofilm formation in a mammary gland, was poorly answered overall.
