Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
ENZYME TECHNOLOGY QUESTIONS 1. (a) What is an extracellular enzyme? ..................................................................................................................................... ..................................................................................................................................... (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; ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (ii) (2) in a medium containing little protein in the second part of the production process. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (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. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (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? ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (ii) Explain the advantage of using an immobilised enzyme in this reactor. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (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. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (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? ..................................................................................................................................... (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. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (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. ................................................................................................................................. ..................................................................................................................................... 2. ................................................................................................................................. ..................................................................................................................................... (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? .................................................................................................................. (1) (ii) Suggest one method which could be used to separate the fungal cells from the liquid medium .................................................................................................................. (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? .................................................................................................................. .................................................................................................................. (1) (c) What evidence from the flow chart suggests that cholesterol oxidase is an intracellular enzyme? .................................................................................................................. .................................................................................................................. (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 ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 6 marks)