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Date November 2018 Marks available 2 Reference code 18N.3.HL.TZ0.9
Level Higher level Paper Paper 3 Time zone TZ0 / no time zone
Command term Outline Question number 9 Adapted from N/A

Question

Outline the characteristics which would indicate biofilm formation in Bacillus subtilis.

[2]
a.

The formation of hydrophobic concrete is an example of how biofilms can be useful. Outline one example where biofilms can cause environmental problems.

[2]
b.

Markscheme

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 ✔

a.

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 ✔

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Option B: Biotechnology and bioinformatics » Option B: Biotechnology and bioinformatics (Core topics) » B.3 Environmental protection
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Option B: Biotechnology and bioinformatics » Option B: Biotechnology and bioinformatics (Core topics)
Option B: Biotechnology and bioinformatics

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