IGCSE Biology Biotechnology & GM topical questions

State two reasons why bacteria are useful in biotechnology.

1. (a)State one reason connected to how quickly they multiply.[1]
2. (b)State one reason connected to what they can produce.[1]

Yeast is used in both bread-making and biofuel production.

1. (a)Name the type of respiration yeast uses in both processes.[1]
2. (b)Write the word equation for this respiration.[1]
3. (c)State the product wanted in bread-making and its effect on the dough.[1]
4. (d)State the product wanted in biofuel production.[1]

Define genetic modification and outline one example.

1. (a)Define genetic modification.[1]
2. (b)Outline one example of genetic modification and its benefit.[2]

Yeast carries out the same anaerobic respiration reaction in a bread dough and in a biofuel fermenter.

1. (a)Name the substance yeast respires to carry out this reaction.[1]
2. (b)Name the product that makes bread rise.[1]
3. (c)Name the product collected as biofuel.[1]
4. (d)Explain why bread contains no alcohol even though yeast makes some.[1]

A food scientist tests pectinase on apple pulp.

1. (a)State what pectinase acts on and where it is found.[2]
2. (b)Describe an investigation comparing juice yield with and without pectinase.[2]
3. (c)State the expected results.[1]

Explain why biological washing powders remove protein stains more effectively in warm water than in boiled water.

1. (a)Name the type of biological molecule in the stains that the enzymes digest.[1]
2. (b)Explain why the enzymes work well in warm water.[2]
3. (c)Explain why they fail in boiled water.[2]

Explain the use of lactase in producing lactose-free milk. (Extended)

1. (a)Name the substrate of lactase and the two products of its action.[3]
2. (b)Explain why this helps lactose-intolerant people.[2]

A fermenter produces a pharmaceutical protein using bacteria. The table shows how yield changed with the temperature of the fermenter.

1. (a)State the optimum temperature from the data.[1]
2. (b)Calculate the percentage increase in yield between 10 °C and 23.5 °C. Show your working.[2]
3. (c)Explain why the pH and the oxygen supply are controlled in the fermenter.[2]
4. (d)State why the fermenter is sterilised with steam before use.[1]

Three washing powders are tested on identical egg-yolk (protein) stains at 40 °C.

1. (a)Identify which powder removes the most stain.[1]
2. (b)Calculate how many percentage points more stain powder A removes than powder B.[1]
3. (c)Explain why powder A removes much more stain than powder B.[2]
4. (d)Suggest why powder C is the best choice for a household with many different kinds of stains.[1]

Explain why bacteria are the organisms of choice for genetic modification on an industrial scale. (Supplement)

1. (a)State three reasons why bacteria are useful in biotechnology and genetic modification.[3]
2. (b)State one ethical advantage of using bacteria rather than animals to make human proteins.[1]
3. (c)State one safety measure used when growing GM bacteria in fermenters.[1]

A juice company tests pectinase on batches of 100 g of apple pulp. The batch with pectinase gives 68 cm³ of juice; the batch without gives 45 cm³.

1. (a)Calculate the percentage increase in juice yield caused by the pectinase. Show your working, giving your answer to one decimal place.[2]
2. (b)Explain how pectinase increases both the volume and the clarity of the juice.[2]
3. (c)State two variables that must be controlled to make the comparison fair.[1]
4. (d)State why the treated juice is safe to drink even though it contains pectinase.[1]

Describe how bacteria are used to produce a human protein, and explain the conditions controlled in the fermenter. (Extended)

1. (a)Outline the genetic modification steps from human gene to bacterial protein.[4]
2. (b)Explain two conditions controlled in the fermenter and why.[3]

Discuss the advantages and disadvantages of growing GM soya, maize and rice. (Extended)

1. (a)Explain two advantages of GM crops.[4]
2. (b)Explain two disadvantages of GM crops.[3]

A farmer compares an insect-resistant GM maize with a non-GM variety.

1. (a)Calculate the percentage increase in yield of the GM maize over the non-GM maize. Show your working, giving your answer to one decimal place.[2]
2. (b)Calculate the total cost per hectare (pesticide plus seed) for each variety.[2]
3. (c)State one advantage and one disadvantage of the GM maize for this farmer.[2]