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Question 17N.3.HL.TZ0.11b

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Date November 2017 Marks available [Maximum mark: 1] Reference code 17N.3.HL.TZ0.11b
Level HL Paper 3 Time zone TZ0
Command term State Question number b Adapted from N/A
b.
[Maximum mark: 1]
17N.3.HL.TZ0.11b

The scanning electron micrograph shows a biofilm on a metal surface from an industrial water system.

[Source: Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms, Rodney M. Donlan, J. William Costerton, Clinical Microbiology Reviews, 2002, 15 (2), pp. 167–193. Reproduced with permission from American Society for Microbiology]

(b)

State a positive application of biofilms.

[1]

Markscheme

a. sewage/waste water treatment/trickle filter beds

b. «bio»remediation of contaminated soil/water

c. metal extraction from ore deposits/microbial leaching

Accept other valid positive application

eg: decay/breakdown contaminants, such as petroleum

[Max 1 Mark]

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