Genetically Modified Organisms in Agriculture (CIE A Level Biology)

A group of scientists have developed a genetically modified crop variety that exhibits increased resistance to a common agricultural pest. The modified plant produces a protein that is toxic to the pest when ingested, reducing crop damage and increasing yields.

The method used by the scientists involved use of a plasmid vector.

Explain the process of gene transfer and the role of the plasmid vector in this process.

Describe the function of a promotor sequence in the genetic modification process.

Fig. 1 below shows data collected on the GM crop variety described in part (a).

Fig. 1

Explain the correlation between the data in graphs A and B between 1998 and 2006.

[1]

(ii)

Describe how the relationship between the data in graphs A and B changes between 2006-2011.

[2]

[3]

While GM crop varieties are thought to provide many benefits, some are concerned about their increased use.

Suggest and justify one strategy that could be employed to address ethical considerations surrounding genetic modification in agriculture.

AquaAdventure salmon is a form of genetically modified salmon that has become available to consumers in the USA.

Table 1 shows some data presented to the US Food and Drug Authority to promote approval of the GM salmon.

Table 1

Calculate how much faster a 1 kg fish can be produced from a GM salmon compared to a non-GM salmon.

Assume that their mass at birth is the same.

[3]

(ii)

Calculate the difference in daily feed requirements of a 1 kg non-GM salmon compared to a 1 kg GM salmon.

Give your answer in g day^-1.

[2]

AquaAdventure also reported that the GM salmon produced showed evidence of increased resistance to common diseases affecting non-GM salmon.

Discuss the benefits of this to the producer.

Critics of AquaAdventure argue that there is a risk that GM salmon may escape into the wild.

Explain why this may be of concern.

Salty soils can inhibit the growth of crop plants, such as tomatoes, particularly in coastal areas. Scientists have genetically modified some species of tomato to increase their salt tolerance. Fig. 1 shows the process used to introduce a gene for a sodium-pump protein obtained from another species of plant (Arabidopsis), into the genome of tomato plants. The gene resulted in increased tolerance of the tomato plants to high salt soil, without affecting the taste or salt content of the fruit produced.

Fig. 1

Describe one method that could be used to obtain the DNA fragment which contains the gene for the sodium pump protein.

In the process shown in Fig. 1, the required gene sequence is extracted from Arabidopsis and is inserted into the tomato plant. 

Explain why the transgenic tomato plant is able to produce the sodium pump protein despite being a different species to the donor plant.

Explain the evidence from Fig. 1 that the genetically modified tomato plant cells are totipotent.

Suggest two possible ways that cells with the sodium pump gene might be selected in stage 4 of Fig. 1.

Many scientists believe that genetic engineering could help solve the global food crisis by improving the quality and productivity of farmed animals and crop plants. In 2015 AquaAdventure Salmon was approved by the US Food and Drug Authority (FDA) for human consumption.

Scientists combined a growth hormone gene from Chinook salmon (Oncorhynchus tshawytscha) with the promoter gene from a cold-water fish, ocean pout (Zoarces americanus). Ocean pout can thrive in near-freezing waters.

Fig. 1 depicts the new GM salmon alongside non-GM salmon at age 18 months.

Fig. 1

Using the information above to explain the main benefit of this genetic modification process for the producers involved.

The GM salmon in Fig. 1 was deliberately made sterile by scientists.

Suggest why this was done.

Discuss the ethical and social implications of using genetically modified organisms (GMOs) in food production. Use at least one named example in your answer.