Biology 9700 · AS & A Level · Principles of genetic technology
Principles of genetic technology — practice question
The waste water from the textile industry may contain azo-dyes, which are used to provide colour to textiles. Azo-dyes are organic pollutants and may be carcinogenic. White-rot fungi are valuable in environmental pollution treatment because they release extracellular enzymes that can decompose a range of organic pollutants, including azo-dyes. The extracellular enzymes made by white-rot fungi are primary metabolites that are produced in large quantities in continuous culture.
(a(i))[2]
Outline the key operating conditions of continuous culture.
(a(ii))[3]
State three advantages of using continuous culture instead of batch culture for the large-scale production of these enzymes.
(b(i))[4]
Describe the results shown in Table 5.1.
(b(ii))[2]
When a similar experiment was carried out using the free enzymes from fungal cells, all concentrations of azo-dye shown in Table 5.1 were broken down in 12 hours. Suggest why free enzymes break down the azo-dye more quickly than intact white-rot fungal cells.
(c)[3]
These extracellular enzymes may be immobilised on an inert support. Outline the advantages of using immobilised enzymes in the treatment of textile waste water.
Worked solution & mark scheme
This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: “open fermenter with continuous nutrient feed” …