Date | November 2019 | Marks available | 1 | Reference code | 19N.3.SL.TZ0.9 |
Level | Standard level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
Command term | Deduce | Question number | 9 | Adapted from | N/A |
Question
A study was carried out in Brazil on the transfer of pollen (cross-pollination) from transgenic strains to non-transgenic strains of soybean (Glycine max). The transgenic crop was resistant to the herbicide glyphosate. The graph below shows the percentage of cross-pollination between transgenic and non-transgenic crops in fields separated by different distances.
[Source: S Abud, et al., (2007), Gene flow from transgenic to nontransgenic soybean plants in the Cerrado region of Brazil,
Genetics and Molecular Research, 6 (2), pages 445–452]
Suggest one undesirable consequence of cross-pollination involving glyphosate resistant crop plants with other plants.
Using the data, suggest one recommendation to farmers who plant transgenic soybeans.
Agrobacterium tumefaciens stains pink or red with the Gram stain. Deduce from this result what type of bacterium A. tumefaciens is.
Outline how A. tumefaciens is used to introduce genes into soybeans.
Markscheme
transfer of resistance genes to non-transgenic/organic crops
OR
transfer of resistance genes to wild relatives/development of weed resistance ✔
separate fields by at least 5m because at this distance no cross pollination occurs ✔
Needs a reason.
«Gram» negative ✔
a. genes to be transferred are introduced into a tumour-inducing/Ti plasmid/vector ✔
b. ‹embryo, seedling leaf› tissue is damaged/wounded / callus formed ✔
c. A. tumefaciens recognizes/is chemically attracted to damaged/wounded tissue ✔
d. A. tumefaciens transfers tumour-inducing/Ti plasmid/vector into plant cell ✔
e. plasmid integrates into plant cell genome ✔