Download ENZYME TECHNOLOGY QUESTIONS 1. (a) What is an extracellular

ENZYME TECHNOLOGY QUESTIONS
1.
(a)
What is an extracellular enzyme?
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(1)
The graph shows the growth of bacteria in the industrial production of an extracellular protein-digesting enzyme.
Medium containing
a lot of protein
Medium containing
little protein
Number of
bacteria
Time
(b)
Explain why the bacteria are incubated:
(i)
in a medium containing a lot of protein in the first part of the production process;
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(ii)
(2)
in a medium containing little protein in the second part of the production process.
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(c)
(1)
This process is carried out in aseptic conditions which prevent contamination with other species of
bacteria. Give one reason why it is necessary to prevent contamination with other species of bacteria.
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(2)
(Total 6 marks)
2.
Lactose is a sugar found in milk. Many adults cannot digest lactose. The diagram shows an industrial reactor
which can be used to reduce the amount of lactose present in milk.
Enzyme reactor at 7 °C
Sterilised
skimmed milk
Immobilised lactase
Lactose-reduced
milk
Recirculation
(a)
(i)
What is an immobilised enzyme?
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(2)
(ii)
Explain the advantage of using an immobilised enzyme in this reactor.
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(2)
(b)
The contents of this reactor are kept at 7°C. Use this information to suggest why it was necessary to
pass the milk through the reactor several times in order to reduce the amount of lactose enough.
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(2)
(Total 6 marks)
3.
In the tanning industry, the production of leather from animal skins involves a number of stages. These
include the removal of natural oils and fats from the skin and the removal of hair. In modern tanneries, these
processes are usually carried out with enzymes. Greasex is an enzyme which hydrolyses triglycerides.
(a)
What are the products when triglycerides are treated with Greasex?
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(1)
(b)
Greasex removes the oils and fats from the skin. Use your knowledge of enzyme structure to explain
why a different enzyme must be used to remove the hair.
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(2)
(c)
Explain two possible advantages of immobilising the Greasex in beads before using it to remove the
oils and fats from the skin.
1. .................................................................................................................................
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2. .................................................................................................................................
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(2)
(Total 5 marks)
4.
The enzyme cholesterol oxidase is used to measure cholesterol concentration in blood samples. The fungus
Aspergillus niger produces cholesterol oxidase.
The flow chart summarises the procedures used to isolate and purify cholesterol oxidase.
Fungal cell grown in
liquid medium inside
a fermenter
Cells separated from
the liquid medium
Separated
fungal cells
(a) (i) What term describes the stages of isolating and purifying an
enzyme produced in a fermenter?
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(1)
(ii) Suggest one method which could be used to separate the fungal
cells from the liquid medium
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(1)
Cells broken open
Mixture of cell debris,
unwanted proteins
and cholesterol oxidase
Expensive
purification stages
Pure solution of
cholesterol oxidase
(b) Why must amino acids be present in the liquid medium inside the
fermenter?
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(1)
(c) What evidence from the flow chart suggests that cholesterol
oxidase is an intracellular enzyme?
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(1)
(d)
The fungal cells used to produce the cholesterol oxidase are grown in aseptic conditions. This prevents
the growth of unwanted microorganisms in the liquid medium. Suggest and explain one reason why
the growth of unwanted microorganisms would make cholesterol oxidase more expensive to produce
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(2)
(Total 6 marks)