DP Biology (last assessment 2024)

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Question 18M.3.SL.TZ1.11

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Date May 2018 Marks available [Maximum mark: 4] Reference code 18M.3.SL.TZ1.11
Level SL Paper 3 Time zone TZ1
Command term Explain Question number 11 Adapted from N/A
11.
[Maximum mark: 4]
18M.3.SL.TZ1.11

Explain the difficulties of treating microorganisms growing in biofilms.

[4]

Markscheme

a. biofilms show properties that are not shown by the individual cells / biofilms develop emergent
properties 

b. quorum sensing changes microbial behaviour / biofilms produce a matrix 

c. (matrix) hard to remove from a surface 

d. biofilms are tolerant to desiccation and heat shock 

e. biofilms may be very resistant to the action of (many) antibiotics/antimicrobial agents 

f. because cell division in biofilms is slow, antibiotics targeting this will be ineffective
OR
matrix forms a barrier to antibiotics

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