In 1973 a technique for genetic engineering was used for the first time. Recombinant DNA was made using a plasmid and this was successfully transferred into an organism. In 2012 a new technique for genetic engineering, called gene editing, was developed.

1. (a)Table 4.1 lists some statements about the two genetic engineering techniques. Complete Table 4.1 to compare the original genetic engineering technique using a plasmid vector with the newer technique of gene editing. For each row, place a tick (✔) in the correct column if the statement applies and leave a blank if the statement does not apply. Table 4.1 statement genetic engineering using a plasmid gene editing It can produce a transgenic organism. It can modify the characteristics of an organism. It can delete unwanted DNA. It uses an enzyme that cuts DNA. It can use RNA to precisely locate the target gene.[5]
2. (b)(i)Orange trees, Citrus sinensis, produce fruits that are an important food crop. The functional leaf area of orange trees may be reduced by the growth of citrus canker bacteria. These bacteria cause citrus canker disease. Scientists used gene editing to develop two types of orange tree with different mutations (changes to the DNA). The mutant orange tree leaves showed resistance to citrus canker disease. [Figure 4.1] Identify the letter that represents the wild type orange trees on Fig. 4.1.[1]
3. (b)(ii)Explain the social benefits of this example of gene editing.[3]

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