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Question 17N.3.HL.TZ0.12

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Date November 2017 Marks available [Maximum mark: 5] Reference code 17N.3.HL.TZ0.12
Level HL Paper 3 Time zone TZ0
Command term Describe, List Question number 12 Adapted from N/A
12.
[Maximum mark: 5]
17N.3.HL.TZ0.12
(a)

Beans contribute to flatulence. Alpha-galactosidase, derived from the fungus Aspergillus niger, is an enzyme that breaks down the fibre usually fermented by bacteria, reducing intestinal gas. Describe how alpha-galactosidase would be produced using A. niger in a continuous fermenter.

[3]

Markscheme

a. constant nutrient medium «supply» needed/maintained

b. optimal mixing

c. fermented in sterile bioreactor

d. alpha-galactosidase production/general conditions assayed/screened/monitored «throughout the process»

e. continuous removal of alpha-galactosidase/products

[Max 3 Marks]

(b)

Temperature is a variable that needs to be continually monitored in deep-tank batch fermentation of penicillin. List two other variables that need to be monitored.

 

[2]

Markscheme

a. pH

b. «dissolved» oxygen

 

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