Making ethanol by fermentation
2 marks · HardExplain why a temperature of 35°C is better than 10°C for fermentation of glucose to produce ethanol.
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At 35°C, enzyme activity in yeast is close to optimum, so the reaction is much faster than at 10°C; at 10°C, the reaction is very slow.
Also accept: 10°C is too cold and the yeast's enzymes work slowly; 35°C is near optimum so ethanol is produced faster
Common mistakes: Just saying 35°C is 'warmer'; Not relating to enzyme activity
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Marking points
B1 · 1 mark · States that 35°C is near the optimum temperature for enzyme activity in fermentation
A1 · 1 mark · States that at 10°C, the reaction would be very slow because enzymes work slowly at low temperatures
Worked solution
The optimum temperature for enzyme activity in yeast is between 30°C and 40°C, so at 35°C, fermentation happens efficiently and much faster than at 10°C, where enzyme activity (and thus fermentation) would be very slow.