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Date May 2016 Marks available 1 Reference code 16M.3.HL.TZ0.11
Level Higher level Paper Paper 3 Time zone TZ0
Command term Suggest Question number 11 Adapted from N/A

Question

The dye Reactive Black 5 (RB5) is widely used for dyeing in textile industries. Removal of the dye from factory waste-water is important not only for aesthetic reasons but also because the dye can lead to mutations that may lead to cancer. Paenibacillus is a bacterium that can metabolize the dye.

Suggest one way in which organisms such as Paenibacillus metabolize toxic substances.

[1]
a.

The decontamination system for the removal of the dye uses a surface to which Paenibacillus can attach. Suggest one advantage of providing a surface for attachment.

[1]
b.

Outline another named example of a microorganism used in bioremediation.

[3]
c.

Markscheme

Uses it as an energy source/carbon source/electron acceptor

Do not accept “metabolizes” it.

a.

To allow for the formation of a biofilm
OR
Does not get washed away/can be re-used

Increases surface area which increases contact between bacteria and dye

b.
Name of microorganism eg: Pseudomonas. Must use at least Genus name.
Name of pollutant eg: oil
Outline of action eg: uses oil as energy/carbon source OR degrades oil
Allow other valid checked examples
 
c.

Examiners report

Some candidates had difficulty with this but many were able to give one way the dye was used by the bacterium.

a.

Some were able to achieve the mark by using the term ‘biofilm’ while others understood the concept but did not seem to be familiar with the term.

b.

This was a relatively easy 3-mark question on bioremediation but a few missed out on details or confused organisms and actions.

c.

Syllabus sections

Option B: Biotechnology and bioinformatics » Option B: Biotechnology and bioinformatics (Core topics) » B.3 Environmental protection
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