Read the following passage carefully and answer the given questions.
During anaerobic sludge digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. These gases form biogas and can be used as source of energy as it is inflammable. The bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum. You must have noticed that bottled fruit juices bought from the market are clearer as compared to those made at home. This is because the bottled juices are clarified by the use of pectinases and proteases. Statins produced by the yeast Monascus purpureus have been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol. The BOD test measures the rate of uptake of oxygen by micro-organisms in a sample of water and thus, indirectly, BOD is a measure of the organic matter present in the water.
The bottled juices are clarified by the combination of -
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Pectinases and proteases
Option (1) Proteases and streptokinase — Incorrect. Proteases are right, but streptokinase is a ‘clot buster’. It is made by the bacterium Streptococcus and removes clots from the blood vessels of heart-attack patients. It has no use in juices.
Option (2) Saccharomyces and Penicillium — Incorrect. These are microbes, not enzymes. Saccharomyces ferments juices into alcoholic drinks such as wine, and Penicillium gives the antibiotic penicillin.
Option (3) Pectinases and proteases — Correct. Pectin from the plant cell walls and proteins from the fruit make home-made juice cloudy. Pectinases break down pectin and proteases break down proteins, so the bottled juice becomes clear.
Option (4) Pectinases and Trichoderma — Incorrect. Pectinases are right, but Trichoderma is a fungus. Its species are used as biocontrol agents against plant diseases, and T. polysporum gives cyclosporin A.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.