Question 19N.3.HL.TZ0.c
| Date | November 2019 | Marks available | [Maximum mark: 3] | Reference code | 19N.3.HL.TZ0.c |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Explain | Question number | c | 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]
Explain the use of Pseudomonas in bioremediation.
[3]
a. used to clean up oil
OR
used to clean up mercury ✔
b. used after other clean-up methods have been used ✔
c. nutrient concentrations have to be sufficient to support the maximal growth rate of the bacteria throughout the clean-up operation ✔
d. converts methylmercury into inorganic mercury «less toxic» ✔
e. converts oil into CO2, water and simpler compounds «non-pollutant» ✔
f. produces extracellular digestive enzymes «lipase» ✔
