18.2 Genetic Modification | Cambridge O Level Biology Topic Questions 2023

1a

3 marks

Genetic modification is a technique that can be used to create many useful substances.

Define the term genetic modification.

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1b

2 marks

Fig. 1 shows part of the process of genetic modification.

enzyme-to-bacteria

Fig. 1

(i)

Identify structure A.

[1]

(ii)

Describe the function of structure A in the process of genetic modification.

[1]

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1c

2 marks

Structure A and B contain 'sticky ends'.

Explain the purpose of these.

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1d

3 marks

Enzyme X plays an important role in the process of genetic modification.

(i)

Identify enzyme X and state its purpose in genetic modification.

[2]

(ii)

Enzyme X leads to the formation of structure C. Give the name of structure C.

[1]

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1a

2 marks

Tissue plasminogen activators (TPAs) are human proteins that are used as drugs to break down blood clots.

TPAs break down blood clots by activating plasminogen. Plasminogen is a protein that is always present in the blood.

When activated, plasminogen forms a protease that breaks down fibrin molecules.

(i)

Plasminogen is found in the plasma.

State what is meant by the term plasma.

[1]

(ii)

State the products of the action of protease on the protein fibrin.

[1]

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1b

8 marks

TPAs can be produced by genetically-engineered bacteria.

Fig. 1 shows some of the stages involved in genetically engineering a bacterium to make a TPA.

cie-igcse-2019-paper4-5b

Fig. 1

(i)

State the name of structure A in Fig. 1.

[1]

(ii)

In the flow chart, X represents the action of an enzyme on a molecule of DNA.

State the name of this enzyme.

[1]

(iii)

The TPA gene is inserted into structure A.

Explain how the gene is inserted into structure A to form structure B as shown in Fig. 1.

[3]

(iv)

Before TPA was made by genetically-engineered bacteria it was only available from blood donated by people.

Suggest one advantage of producing TPA by genetically-engineered bacteria.

[1]

(v)

The genetically-engineered bacteria produce mRNA that is a copy of the human TPA gene.

Explain the role of mRNA in the bacterium.

[2]

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1a

1 mark

Bacteria are useful in biotechnology and genetic engineering.

Fig. 1 shows a photomicrograph of a bacterium.

screenshot-2022-10-12-16-17-39

Fig. 1

State the name of the process that is taking place in Fig. 1.

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1b

2 marks

(i)

Write the formula that would be used to calculate the actual width of the bacterium.

[1]

(ii)

The actual width of the bacterium is 0.0008 mm.

Convert this value to micrometres (μm).

[1]

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1c

6 marks

Genetically modified bacteria can produce human insulin.

(i)

State the name of the disease that can be treated with insulin injections.

[1]

(ii) Insulin is a protein.

Describe the process of using bacteria in genetic engineering to produce human proteins.

[5]

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1d

6 marks

Genetically modified bacteria are often grown in fermenters.

(i)

Suggest why steam is used to clean fermenters.

[2]

(ii)

State three conditions inside a fermenter that are measured and controlled.

[3]

(iii)

State the name of one commercial product, other than insulin, that is made in fermenters.

[1]

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1e

4 marks

Crop plants can also be genetically modified.

Describe the advantages of genetically modifying crops.

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Genetic Modification (Cambridge O Level Biology)

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