Microbes and Human Welfare MCQs for NEET — Botany Questions with Answers

Cheese and toddy are obtained through the process of fermentation. In cheese production, milk is fermented using specific bacteria to produce lactic acid, which helps coagulate the milk proteins. Toddy, a traditional alcoholic beverage, is made by fermenting the sap of palm trees using natural yeasts.

• (1) Causes souring of milk by increasing nutritional quality
• (2) Increases the amount of vitamin-b12
• (3) Checks disease causing microbes
• (4) It produces acid which coagulate and partially digest the milk proteins

The odd pair is Streptococcus - Stetins. Streptococcus is a genus of bacteria known for causing various infections, including strep throat, but it is not associated with the production of statins. Statins are a class of lipid-lowering medications that are typically produced by fungi such as Penicillium and Aspergillus. Therefore, this pair does not match the way the other pairs do.

Bt cotton refers to genetically modified cotton that contains a gene from Bacillus thuringiensis (Bt). This gene produces an endo toxin that is harmful to certain pests, such as the bollworm, thus providing protection to the cotton plant.

Azospirillum and Azotobacter are examples of free-living nitrogen-fixing bacteria. These bacteria can convert atmospheric nitrogen into a form that plants can absorb and use for their growth, which is essential for non-leguminous plants.

Biogas provides both fertilizer and energy. The process of anaerobic digestion of organic matter produces biogas, which can be used as a source of energy, and the residue left behind can be used as a nutrient-rich fertilizer.

The Bt toxin produced by Bacillus thuringiensis (Bt) is a protein that becomes toxic when ingested by insects. After ingestion, the toxin is activated in the alkaline conditions of the insect's gut, binds to the gut wall, creates pores, and ultimately leads to the insect's death. This makes option o4 correct.