DP Biology (last assessment 2024)

Question 18M.3.SL.TZ1.a

Date	May 2018	Marks available	[Maximum mark: 1]	Reference code	18M.3.SL.TZ1.a
Level	SL	Paper	3	Time zone	TZ1
Command term	Identify	Question number	a	Adapted from	N/A

[Maximum mark: 1]

18M.3.SL.TZ1.a

Citric acid is produced industrially from sugars in continuous fermenters using the fungus Aspergillus niger and with date syrup as a growth medium. Citric acid is a byproduct of the metabolism of this fungus. The fungus requires a nitrogen source for optimal growth and the impact of different nitrogen sources on citric acid production was investigated. The control received no additional nitrogen.

Identify the nitrogen source that results in the highest yield of citric acid.

[1]

Markscheme

NH₄NO₃ / ammonium nitrate

Syllabus sections

Option B: Biotechnology and bioinformatics

Option B: Biotechnology and bioinformatics » Option B: Biotechnology and bioinformatics (Core topics) » B.1 Microbiology: organisms in industry

Option B: Biotechnology and bioinformatics » Option B: Biotechnology and bioinformatics (Core topics)

Question 18M.3.SL.TZ1.a

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