A-LevelBiologyGenetic technology9700/42 · May/June 2019 · Q39 Marks

Soybean, Glycine max, is an important food crop for human consumption and for feeding to animals. Two varieties of soybean are Vinton 81 and GTS 40-3-2. Vinton 81 has been developed in the traditional way by selective breeding (artificial selection) and GTS 40-3-2 is an example of a genetically modified (GM) organism.

(a)GTS 40-3-2 is described as herbicide-resistant, as it can withstand the application of glyphosate herbicide. Glyphosate is sprayed on the crop to kill weeds. Outline how genetic engineering gave GTS 40-3-2 the trait of herbicide resistance.[4]
(b)Countries vary in the extent to which they grow GM varieties, such as GTS 40-3-2, instead of traditional varieties such as Vinton 81. In the USA, 94% of soybeans grown are GM. In Europe, 0% of soybeans grown are GM. Scientists used computer models to predict the effect of two different changes in agricultural practice on soybean crop yields: a global ban that reduces the cultivation of GM soybeans to 0% everywhere all countries increasing the cultivation of GM soybeans to the 94% level of the USA. Table 3.1 shows the results of this modelling for four countries. [Table 3.1] Explain what the data in Table 3.1 suggests about the social and ethical implications of growing GM soybeans.[5]

Mark scheme

Marking points from the official mark scheme (May/June 2019). The mark or mark type is shown in brackets.

[4] any four from:
1 gene (for herbicide resistance) from, another species / variety / (soil) bacterium; A allele
2 ref. to restriction enzyme ;
3 ref. to (Ti) plasmid / vector / Agrobacterium/gene gun ;
4 (DNA) ligase;
5 ref. to recombinant, DNA / plasmid ;
6 introduced into soybean, cells / genome / DNA; I embryos
7 (new) gene, expressed / transcribed ;
8 (to produce) protein / enzyme, resistant to, glyphosate / herbicide ;
9 AVP; e.g. ref. to tissue culture / produce callus / detail such as grow cells on growth medium / marker genes / insert promoter
[5] any five from:
1 decrease / ban / 0%, GM soybean (cultivation), decreases yield;
2 use GM soybean, more / 94%, increases yield;
use GM crops – accept ora throughout if GM crops banned
3 increase food supply / decrease food cost;
4 relieve, hunger / starvation;
5 less / more, herbicides used; correct context needed
6 less / more, money spent on herbicides ; correct context needed
7 increase profits / improve economy ;
8 unknown health consequences; (can be positive or negative)
9 high cost of GM seed ;
10 idea of decrease in, genetic variation / biodiversity;

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