Question 18N.3.HL.TZ0.9
| Date | November 2018 | Marks available | [Maximum mark: 4] | Reference code | 18N.3.HL.TZ0.9 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Outline | Question number | 9 | Adapted from | N/A |
Outline the characteristics which would indicate biofilm formation in Bacillus subtilis.
[2]
a. bacteria/B. subtilis adhere to surfaces ✔
b. «bacteria/B. subtilis» grow surrounded by EPS/exopolysaccharide/extracellular polymeric substance matrix ✔
c. «bacteria/B. subtilis growing in a biofilm» are highly resistant to antimicrobial agents ✔
d. «bacteria/B. subtilis in biofilms» cooperate through quorum sensing ✔
The formation of hydrophobic concrete is an example of how biofilms can be useful. Outline one example where biofilms can cause environmental problems.
[2]
a. example of where biofilm cause problems ✔
eg: clogging/corrosion of pipes/water systems ✔
slows down/interrupts/clogs water supply systems ✔
OR
eg: contamination of surfaces in food production ✔
causes food transmitted diseases ✔
OR
eg: plaque formation on teeth ✔
causes cavities ✔
OR
eg: catheter clogging ✔
causes urinary infections ✔
b. description of problems ✔