Read the following passage carefully and answer the given questions.
Bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum. 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. Baculoviruses are pathogens that attack insects and other arthropods. The majority of baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus. These viruses are excellent candidates for species-specific, narrow spectrum insecticidal applications. They have been shown to have no negative impacts on plants, mammals, birds, fish or even on non-target insects. BOD refers to the amount of the oxygen that would be consumed if all the organic matter in one liter of water were oxidised by bacteria. The sewage water is treated till the BOD is reduced. Cheese, is one of the oldest food items in which microbes were used. Different varieties of cheese are known by their characteristic texture, flavour and taste. For example, the large holes in 'Swiss cheese' are due to production of a large amount of CO2 by a bacterium named Propionibacterium sharmanii.
The greater the BOD of waste water-
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → The more is its polluting potential
Option (1) The more is its polluting potential — Correct. A high BOD means much organic matter. Bacteria breaking it down use up the oxygen of the water, and fish and other water animals die.
Option (2) The less is its polluting potential — Incorrect. This is the reverse. Sewage is treated until its BOD falls, because a low BOD means less pollution.
Option (3) The greater will be the oxygen — Incorrect. BOD is the oxygen that will be consumed, not oxygen present in the water. The higher it is, the less oxygen is left.
Option (4) The lesser will be the methane gas — Incorrect. BOD says nothing about methane. Methane forms later, when anaerobic bacteria digest the sludge of sewage treatment and give biogas.
Note 1: 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.
Note 2: A similar question was also asked in CUET (UG) 2023 on 31-05-2023 (Slot 3).
NCERT Extract:
Microbes in Sewage Treatment – “… The greater the BOD of waste water, more is its polluting potential.”
