Question 19M.3.HL.TZ2.a.ii
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.HL.TZ2.a.ii |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Suggest | Question number | a.ii | Adapted from | N/A |
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]
a. polysaccharide matrix/EPS does not let antibiotic pass/limits transport of antibiotic ✔ OWTTE
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 ✔
Most candidates seem to have a very good knowledge of biofilms, but it was more difficult to outline quorum sensing properly and suggest a reason for antibiotic resistance.
