Given an example of a rod-shaped virus.
Tobacco mosaic virus is a rod-shaped virus. This is the first plant virus to be discovered.
What is the group of bacteria found in both the rumen of cattle and sludge of sewage treatment?
Methanogens (Methanobacterium), anaerobically break down cellulosic material to produce $\mathrm{CO}_2$ and $\mathrm{H}_2$, and are found in
(i) Anaerobic sludge in sewage treatment plants.
(ii) Rumen (a part of stomach) of cattles, thus providing nutrition to cattles.
Name a microbe used for the production of swiss cheese.
Cheese is formed by partial degradation of milk by different microorganisms. Swiss cheese is formed by the bacterium Propionibacterium sharmanii. Its characteristic feature is formation of large holes due to production of large amount of $\mathrm{CO}_2$.
Why are flocs important in biological treatment of waste water?
Flocs are masses of bacteria associated with fungal filaments that form mesh like structures. These are important in biological treatment of waste water, as they help in digestion of organic matter, remove pathogens and release nutrients in the sewage effluent.
How has the bacterium Bacillus thuringiensis helped us in controlling caterpillars of insect pests?
Bacillus thuringiensis produces an are endotoxin which, when ingested and released in the gut of the larvae of insect pest disrupts the insect gut lining thereby killing them.