Genetic Modification (Edexcel GCSE Biology: Combined Science)

Exam Questions

2 hours13 questions
1a
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2 marks

Higher Tier Only

The process of genetic engineering involves the use of vectors.

(i)
Define the term vector when used in the context of genetic engineering. 

(1)

(ii)

Name one example of a vector used in genetic engineering.

(1)

1b
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3 marks

Higher Tier Only

The table below sets out a number of steps in the production of human insulin in a process that involves genetically-engineered bacteria. 

The statements are in the wrong order. 

A A plasmid is cut using restriction enzymes.
B The transgenic bacterial cells are grown in a fermenter.
C The recombinant plasmid is taken up by bacterial cells.
D The cut plasmids are mixed with copies of the human insulin gene.
E The plasmid and the human insulin gene are joined by DNA ligase.

Complete the blank table below to list the steps in the correct sequence.

The first step has been completed for you. 

Step Corresponding letter from the table above
1 A
2  
3  
4  
5  

1c
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2 marks

Define the term transgenic.

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2a
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1 mark

A global study was carried out on the production of high protein maize.

Over 100 generations, scientists planted seeds which were the most protein rich from the previous generation, they then measured the percentage of protein in the corn kernels.

What is the name given to the process used by these scientists to produce maize with a high percentage of protein?

2b
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3 marks

The data collected on the percentage of protein content in the maize kernels over 100 generations can be seen below.
zsnqzcNt_-per-cent-protein-in-maize-selective-breeding-sq

(i)

Describe the trend on the graph.

(2)

(ii)
Give the percentage of protein after 50 generations.

(1)

2c
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1 mark

High protein maize is considered to be of superior nutritional value and is therefore desirable to food manufacturers.

Which of the following explains why high protein maize provides a superior nutritional value?

  A Protein is required for growth and repair of tissues
  B Protein is an energy source
  C Protein provides roughage in a balanced diet
  D Protein provides insulation for key organs of the body

2d
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2 marks

Suggest why it may be appealing for farmers to invest in growing high protein maize.

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3a
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1 mark

State one example of a trait for which animals are commonly selectively bred.

3b
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1 mark

State one potential risk associated with selective breeding.

3c
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2 marks

Table 1 below shows selectively bred plants and their characteristics.

Match the selectively bred plant with its corresponding characteristic.

Table 1

Characteristics Selectively bred plants
A) Disease resistance in food crops Apple trees
B) Large or unusual flowers Wild Brassica
C) Increased crop yield Wheat
D)  Better tasting fruits Orchids

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4a
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1 mark

“Cystic fibrosis results from one or more __________ in a person's genome.”

Fill in the blank. 

4b
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2 marks

Higher Tier Only

List two uses of restriction enzymes in genetic engineering. 

4c
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3 marks

Higher Tier Only

Define the term "recombinant plasmid" in the context of genetic engineering.

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1a
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4 marks

Higher Tier only

Name, and describe the roles of, the main enzymes used in genetic engineering.

1b
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2 marks

Genes from the bacterium Bacillus thuringiensis can be extracted and inserted into crop plants.

Explain the benefit of this example of genetic engineering to farmers. 

1c
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2 marks

Genetic engineering changes the genome of a species more extensively than selective breeding.

Suggest why. 

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2a
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4 marks

Figure 1 shows a selectively-bred bull from the variety of beef cattle known as the Belgian blue.

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Figure 1

Use your knowledge of selective breeding to suggest two benefits and two drawbacks of breeding from the bull shown in Figure 1

2b
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1 mark

The owner of the bull shown in Figure 1 is able to extract the bull's semen and sell that to other cattle breeders to allow their cows to become pregnant with this bull's offspring. This practice is called artificial insemination (AI). 

State one advantage of farmers using AI during selective breeding. 

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3a
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2 marks

Higher Tier only

Explain the meaning of the term 'vector' when used in genetic engineering. 

3b
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3 marks

Higher Tier only

The table in Figure 5 sets out a number of steps in the production of human insulin in a process involving genetically-engineered bacteria. 

The statements are in the wrong order. 

A A plasmid can be cut with the same restriction enzymes.
B DNA ligase anneals (joins) lengths of DNA together.
C The recombinant plasmid is inserted into a bacteria and grown to produce insulin.
D Restriction enzymes are used to cut the insulin gene out of a human genome.
E The genes and plasmids are mixed.
F Sticky ends are left at the ends of the gene.

Figure 5

Complete the table in Figure 6 to list the steps in the correct sequence.

The first step has been completed for you. 

1st step D
2nd step  
3rd step  
4th step  
5th step  
6th step  

Figure 6

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4
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5 marks

Higher tier content only

Yeast cells can be genetically modified to produce a painkiller.

This painkiller is usually obtained from opium poppies.

One method for genetically modifying a yeast cell uses a plasmid containing the desired gene.

(i)
Explain how a gene can be inserted into a plasmid.
(2)
(ii)
Discuss the possible benefits and risks of producing painkillers from genetically modified yeast cells rather than extracting the painkillers from poppies.
(3)

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5
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6 marks

Figure 1 shows two varieties of potato plant.fig-14-1bio-1f-june18-qp-gcse-bio

Figure 1


New varieties of potato plant can be produced by selective breeding.

Explain how selective breeding of the two varieties of potato plants can produce new potato plants that are all faster growing and produce many, large potatoes.

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6
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3 marks

Figure 1 shows a plasmid containing the human insulin gene.fig-8-1bio-1h-june19-qp-gcse-bio


Figure 1

Explain how the human insulin gene can be inserted into a plasmid.

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7a2 marks

Figure 1 shows some information about two types of cattle.

type of cattle

survival in high temperatures

meat quality
Brahman good poor
Shorthorn poor good

Figure 1

Describe how these types of cattle could be selectively bred to produce cattle that can survive high temperatures and have good meat quality.

7b2 marks

Figure 2 shows the leaf of a wheat plant with a fungal disease.

fig-5-1bio-1f-nov2021-qp-gcse-bio

Figure 2

Give two benefits of breeding wheat plants that are resistant to fungal disease.

1 ....................................................

2 ....................................................

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1a
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6 marks

Genetically modified (GM) crops have been on the market since the 1990s. This biotechnology involves changing the DNA of one organism, often by inserting genes from another.

GM maize makes up more than 87% of all maize grown in the United States. The maize has been modified to contain the pesticide Bt, making it toxic to insects that try to eat it. The gene that makes Bt comes from the bacterium Bacillus thuringiensis, which produces a toxin that kills insects. 

(i)
Describe how the gene can be transferred from the bacterium, Bacillus thuringiensis, to the maize crop.

(3)

(ii)
Explain why farmers might want to grow GM crops that are resistant to pests.

(3)

1b
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7 marks

Figure 1 shows the number of Bt crops and the number of resistant species in an 80 hectare farm in the United States.4-2-gcse-edexcel-4-2h-q4-bt-crops

Figure 1

(i)
Calculate the percentage increase in Bt crops from 2011 to 2022. 

Give your answer to 1 decimal place.

(2)

(ii)
Explain the pattern shown by the data in the graph.

(5)

1c
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4 marks

Discuss why some people might disagree with the production of genetically modified crops.

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2a
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6 marks

Recent studies have shown that cancerous tumours can be targeted using genetically engineered bacteria. Research has shown that where chemotherapy and radiotherapy have been unsuccessful in treating cancerous tumours, the answer may lie with the use of bacteria as a therapeutic agent.

A group of bacteria, called Clostridium, can be modified with a gene that causes the bacteria to produce proteins which have been shown to destroy tumours.

(i)
Explain how the Clostridium bacteria can be genetically modified to produce the tumour-destroying proteins.

(4)

(ii)
Recent studies carried out on mice showed that genetically modified bacteria, when applied to the skin of mice infected with skin cancer, were successful in slowing or preventing the growth of 15 out of 16 cancerous tumours. 

A scientist has concluded that genetically engineered bacteria is the most effective treatment for cancer.

Suggest two reasons why this conclusion may not be valid.

(2)

2b
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7 marks

Selective breeding is another method used by humans so that organisms have desirable characteristics, such as selectively breeding cows to produce large volumes of high-quality beef.

The graph in Figure 1 shows information about the mass of beef produced by cattle in Ireland from 2012 to 2022. 

4-2-gcse-edexcel-4-2h-q5-beef-production

Figure 1

(i)
Give the mean mass of beef produced from 2012 to 2022.

Give your answer in tonnes in standard form. 

(2)

(ii)
Suggest why traits such as producing more beef might not have developed due to natural selection.

(3)

(iii)
Explain two disadvantages of selectively breeding cows to produce more beef. 

(2)

2c
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3 marks

Some people believe that selective breeding can cause issues with inbreeding. 

The pug is an ancient breed of dog which, in recent years, has suffered from issues caused by inbreeding. 

Figure 2 shows data collected about heart failure in pugs over a 12 month period in Boston, USA.

4-2-edexcel-gcse-4-2h-sq-q2-pugs

Figure 2

(i)
Describe how the incidence of heart failure in pugs changed from January to December. 

Use data from Figure 2 in your answer.

(2)

 

(ii)
Other than the risk of heart failure, give one other reason why people might disagree with selectively breeding pugs.

(1)

2d
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6 marks

Evaluate the benefits and risks of genetic engineering and selective breeding in modern agriculture.

You should include the practical and ethical implications in your answer.

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