O-LevelBiologyRespiration5090/21 · May/June 2014 · Q910 Marks
Outline the role of a named type of microorganism in the production of each of the following products. bread type of microorganism role yoghurt type of microorganism role
- (a)Outline the role of a named type of microorganism in the production of each of the following products. bread type of microorganism role yoghurt type of microorganism role[4]
- (b)Describe and explain how a fermenter is used to produce the antibiotic penicillin from a named microorganism.[6]
Mark scheme
Marking points from the official mark scheme (May/June 2014). The mark or mark type is shown in brackets.
- [4] bread: fungus/yeast;
- fermentation/ (anaerobic) respiration ;
- CO2 production + dough rises/improves texture of bread ;
- yoghurt: bacteria/bacterium/Lactobacillus ;
- (milk sugar/lactose) to lactic acid ;
- (lactic acid) thickens/clots milk/gives sour taste ;
- [6] Penicillium;
- sterilised + prevent contamination AW ;
- substrate/nutrient medium/culture medium ;
- protein/amino acids provided ;
- for growth;
- carbohydrate/glucose provided ;
- for respiration/ref. energy;
- supply of oxygen/air;
- ref. sparger + bubbles or ref. surface area/paddles + stirring ;
- ref. control of temp;
- ref. control of pH ;
- extraction/filtration/purification/crystallisation ;
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