Question 19N.3.HL.TZ0.11b
| Date | November 2019 | Marks available | [Maximum mark: 1] | Reference code | 19N.3.HL.TZ0.11b |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
Cupriavidus metallidurans CH34 is a heavy metal-resistant bacterium that was genetically modified to be used for bioremediation. The merB gene that controls the conversion of organic mercury into inorganic mercury was introduced in the bacterium. The gel electrophoresis image below shows the presence of the merB gene in two strains after 70 generations.
[Source: Copyright © 2011 Rojas LA, Yáñez C, González M, Lobos S, Smalla K, Seeger M (2011) Characterization of the
Metabolically Modified Heavy Metal-Resistant Cupriavidus metallidurans Strain MSR33 Generated for Mercury Bioremediation.
PLoS ONE 6(3): e17555. https://doi.org/10.1371/journal.pone.0017555]
The generation time of C. metallidurans is a few hours. Two strains of the bacterium were tested for the presence of the merB gene 70 generations after the genetic modification. Suggest one reason for carrying out these tests after 70 generations of the transgenic bacterium.
[1]
to observe that it was stable
OR
to confirm that change was permanent
OR
to confirm that merB gene still present after many generations ✔
