DP Biology (last assessment 2024)

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Question 18N.3.SL.TZ0.11

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Date November 2018 Marks available [Maximum mark: 4] Reference code 18N.3.SL.TZ0.11
Level SL Paper 3 Time zone TZ0
Command term Discuss Question number 11 Adapted from N/A
11.
[Maximum mark: 4]
18N.3.SL.TZ0.11

The micrograph shows a T4 bacteriophage.

Discuss the use of bacteriophages in water systems.

[4]

Markscheme

a. bacteriophages are viruses of bacteria/prokaryotes ✔

b. each bacteriophage is specific to certain bacterial groups
OR
they can be used to target specific bacteria ✔

c. can be used in sewage plants
OR
can kill bacteria that cause water contamination/disinfect water
OR
can kill bacteria that form biofilms at water purification plants ✔

d. can kill strains resistant to antibiotics
OR
can kill strains resistant to chlorine/chemical disinfectants ✔

e. «presence of» bacteriophages also act as indicators of bacteria present ✔

f. generally not harmful to humans ✔

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