DP Biology (last assessment 2024)

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Question 20N.3.HL.TZ0.a

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Date November 2020 Marks available [Maximum mark: 3] Reference code 20N.3.HL.TZ0.a
Level HL Paper 3 Time zone TZ0
Command term Distinguish Question number a Adapted from N/A
a.
[Maximum mark: 3]
20N.3.HL.TZ0.a

Bacteria sometimes form biofilms inside metal pipes in water systems. Distinguish between free bacteria and bacteria in biofilms.

[3]

Markscheme

a. biofilm bacteria are all together while free bacteria do not interact with others;

b. biofilm bacteria present emergent properties not present in free bacteria;

c. quorum sensing only found in biofilm;

d. EPS matrix only in biofilm;

e. biofilm bacteria are more resistant to antibiotics/disinfectants;

Examiners report

Good candidates managed to distinguish between free bacteria and bacteria in biofilms.

Syllabus sections