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Practice each question, then open the answer or worked solution.
Why are flocs important in the biological treatment of wastewater?
Ans: Flocs are crucial in biological wastewater treatment because they aid to lower biological oxygen demand (B.O.D) in the water, making it less polluted and livable for aquatic species, as well as reducing pathogens and decomposing organic waste.
How has the bacterium Bacillus thuringiensis helped us in controlling caterpillars of insect pests?
Ans: The bacteria Bacillus thuringiensis aids in the management of insect pest caterpillars by creating an endotoxin in the caterpillar's midgut when it is consumed by the pest. The endotoxin discharged will kill the insects' midgut lining.
How do mycorrhizal fungi help the plants harbouring them?
Ans: Mycorrhiza is a fungus that aids plants in taking additional nutrients from the soil, such as phosphorus, and transferring them to the host plant. This also aids ion in pulling more water from the soil, allowing plants to better endure environmental circumstances such as drought.
Why are cyanobacteria considered useful in paddy fields?
Ans: Cyanobacteria are thought to be beneficial in rice fields because they fix nitrogen from the air and provide organic matter, which improves soil fertility.
How was penicillin discovered?
Ans: Alexander Fleming discovered penicillin by accident in 1921. When he returned from a trip, he discovered that one of his staphylococcus culture plates had been infected with mold. The mold stopped staphylococcus culture from growing. As a result, he came to the conclusion that the antibiotic was isolated from the fungus Penicillium notatum.
Name the scientists who were credited for showing the role of Penicillin as an antibiotic?
Ans: Alexander Fleming discovered penicillin in 1921 but he was not credited for showing its role as an antibiotic.
How do bioactive molecules of fungal origin help in restoring good health of humans?
Ans: As a variety of bioactive molecules are important in the medical treatment of people, bioactive molecules of fungal origin aid in the restoration of human health.
a) A statin is a drug that helps to decrease cholesterol levels in the blood.
b) Cyclosporin A, an immunosuppressive medication.
c) Lipase is an enzyme that digests lipids in our digestive system as well as removes oil stains.
What roles do enzymes play in detergents that we use for washing clothes? Are these enzymes produced from some unique microorganisms?
Ans: Enzymes such as lipases are employed in detergent formulas to stimulate oil breakdown and so aid in the removal of oily and greasy stains from laundry clothing. Candida lipolytica and Geotrichum candidum are used to make these.
What is the chemical nature of biogas? Name an organism which is involved in biogas production?
Ans: Biogas is made up of three different gases. Methane (\[CH_{3}\]) makes up roughly 60-70 percent of the overall volume, carbon dioxide (\[CO_{2}\]) makes up about 30-40 percent, and hydrogen sulphide makes up about 0.1 percent. The organisms involved in biogas generation are known as methanogens.
How do microbes reduce the environmental degradation caused by chemicals?
Ans: Microbes aid in the reduction of chemical-induced environmental damage. Agriculture is a good example of bioremediation. Bio fertilizers are made up of bacteria that enrich the soil by removing nitrogen from the air. Pesticides that produce an endotoxin that is absorbed by the bug and destroys the midgut lining are also used to kill pests.