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Question 18M.2.SL.TZ2.6a

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Date May 2018 Marks available [Maximum mark: 3] Reference code 18M.2.SL.TZ2.6a
Level SL Paper 2 Time zone TZ2
Command term Outline Question number a Adapted from N/A
a.
[Maximum mark: 3]
18M.2.SL.TZ2.6a

Although simple in structure, bacteria as a group show a wide range of diversity.

(a)

Outline the roles bacteria play in the carbon cycle.

[3]

Markscheme

a. decomposition of dead organic material «by saprotrophic bacteria» 

b. «decomposition» leads to CO2 formation/regeneration due to respiration 

c. «saprotrophic bacteria only» partially decompose dead organic matter in acidic/anaerobic conditions in waterlogged soil 

d. results in peat formation in bogs/swamps 

e. photosynthetic bacteria/cyanobacteria fix CO2 in photosynthesis

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