| Date | November 2017 | Marks available | 3 | Reference code | 17N.3.SL.TZ0.08 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
| Command term | Explain | Question number | 08 | Adapted from | N/A |
Question
The diagram shows a simplified fermenter used in the production of penicillin.
[Source: Valero, F, del Rio, JL, Poch, M and Sola, C (John Wiley and Sons, 1992). Studies on Lipase Production by Candida rugosa Using On-line Enzymatic Analysis. Annals of the New York Academy of Sciences, 665, pp. 334–344.
doi: 10.1111/j.1749-6632.1992.tb42596.x]
State two conditions in the fermenter that would be monitored by the probes.
Suggest a reason that the fermenter is surrounded by a water jacket.
Identify the waste gas produced.
Explain the process of penicillin production in the fermenter.
Markscheme
a. pH
b. temperature
c. oxygen levels
d. viscosity
e. foam
f. carbon dioxide
Accept any two conditions for the mark
[Max 1 Mark]
a. maintain constant temperature/insulation
b. cooling
[Max 1 Mark]
carbon dioxide/CO2
a. inside of fermenter is sterilized «to prevent growth of other organisms»
b. «penicillin» fungus/Penicillium added to fermenter
c. nutrients are provided to allow the fungus to grow
d. when nutrients are used up, penicillin is produced
e. penicillin extracted from mixture in fermenter
f. penicillin purified ready for medical use
Accept named nutrient eg: glucose
[Max 3 Marks]
