1. 1
   A baker mixes live yeast into bread dough and leaves it in a warm place before baking. The dough visibly rises over the next hour. Separately, a fruit juice manufacturer adds an enzyme called pectinase to crushed fruit pulp during the production of clear apple juice.

   (a)

   A baker mixes yeast into bread dough and leaves it in a warm place, causing the dough to rise before baking. Which process carried out by the yeast causes the dough to rise?

   [1 mark]

   • AAerobic respiration, producing oxygen bubbles
   • BAnaerobic respiration, producing carbon dioxide bubbles
   • CPhotosynthesis, producing glucose
   • DActive transport of water into the dough

   (b)

   The fruit juice manufacturer adds the enzyme pectinase to crushed fruit pulp during apple juice production. What is the main purpose of adding pectinase in this process?

   [1 mark]

   • ATo break down pectin in the cell walls of the fruit, releasing more juice and making it clearer
   • BTo add flavour to the juice
   • CTo kill any bacteria present in the fruit pulp
   • DTo increase the sugar content of the juice

   (c)

   Explain what happens to the yeast dough when it is baked, in terms of the gas bubbles produced during fermentation and the effect of high oven temperature on the yeast.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A washing powder manufacturer has developed a new biological detergent containing enzymes that break down protein and fat-based stains at lower washing temperatures than traditional detergents. Separately, a dairy company uses the enzyme lactase to produce lactose-free milk for customers who are lactose intolerant.

   (a)

   A washing powder manufacturer adds biological enzymes to a new laundry detergent to help remove protein and fat-based stains, such as blood and grease, at lower washing temperatures than traditional detergents. What is the main advantage of using enzymes in this way?

   [1 mark]

   • AThey only work at extremely high temperatures above 90 degrees Celsius
   • BThey increase the amount of energy needed to wash clothes
   • CThey allow effective stain removal at lower temperatures, saving energy
   • DThey have no effect on protein or fat-based stains

   (b)

   The dairy company uses the enzyme lactase to produce lactose-free milk. What does lactase do to make this milk suitable for lactose-intolerant customers?

   [1 mark]

   • AIt adds lactose to the milk
   • BIt converts milk protein into fat
   • CIt removes all sugars from the milk
   • DIt breaks down lactose into simpler sugars that lactose-intolerant people can digest

   (c)

   Explain why lactose-intolerant people are unable to digest ordinary milk properly, and explain how treating milk with lactase solves this problem.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A pharmaceutical company uses a large industrial fermenter to grow the mould Penicillium, which produces the antibiotic penicillin. A separate food production company uses a similar fermenter to grow the fungus Fusarium, producing mycoprotein, a protein-rich meat substitute, for the food industry.

   (a)

   Describe how a fermenter is used for the large-scale production of penicillin, and explain why maintaining a suitable nutrient supply within the fermenter is important.

   [3 marks]

   (b)

   Explain why temperature, pH and oxygen supply must all be carefully controlled within a fermenter such as the one producing penicillin or the one producing mycoprotein, referring to the effect of these conditions on the microorganism's enzymes and growth.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A food technology course is reviewing several applications of biotechnology used in the food and drink industry: yeast fermentation in bread-making and biofuel production, the use of pectinase in fruit juice production, and the large-scale industrial fermentation used to produce mycoprotein from the fungus Fusarium.

   (a)

   Explain fully how biotechnology is used in food and drink production, referring to the role of yeast in bread-making and biofuel production through anaerobic respiration, and the role of pectinase in fruit juice production. Explain the biological reason why each of these processes is effective.

   [6 marks]

   (b)

   Explain fully how the fungus Fusarium is grown in industrial fermenters to produce mycoprotein, a protein-rich food used as a meat substitute, including the conditions that must be controlled, and explain why this method of protein production may be considered advantageous compared with traditional methods of producing protein from livestock farming.

   [6 marks]

   Total for question 4: 12 marks

End of questions