OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www wisedane

OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www. wisedane. com

BIOLOGY MICROBES IN HUMAN WELFARE SET 3 MCQ’s

Q 1. Which one of the following is used as biological insecticide? A. Silkmoth B. Caterpillar C. Tiger beetle D. Mazra Poka www. wisedane. com

ANSWER (C) EXPLANATION Ø Tiger beetles are a large group of beetles known for their aggressive predatory habits and running speed. Ø Although small in size, tiger beetles are important predators of the insect world and a favorite among collectors. The scientific community finds tiger beetles excellent models to research ecology, biology, morphology, thermoregulation, predator-prey interactions, biogeography and physiology. www. wisedane. com

Q 2. Which of the following is not used as a biopesticide? A. Trichoderma harzianum B. Bacillus thuringiensis C. Xanthomonas campestris D. Nuclear Polyhedrosis Virus (NPV) www. wisedane. com

ANSWER (C) EXPLANATION Ø Xanthomonas campestris is bacterial species that causes a variety of plant diseases. Black rot, caused by the bacterium Xanthomonas campestris is considered the most important and most destructive disease of crucifers, infecting all cultivated varieties of brassicas worldwide. www. wisedane. com

Q 3. Which one of the following plant is commonly used as green manure? A. Cassia fistula B. Acacia nilotica C. Dalbergia sissoo D. Crotalaria juncea www. wisedane. com

ANSWER (D) EXPLANATION Ø Crotalaria juncea, or sunn hemp, is a member of the pea family (Fabaceae) is grown in many countries as a green manure or forage crop. Originating in South Asia, but with a common cultivar developed in Hawaii, it is a fast-growing, droughttolerant and aesthetically pleasing plant with real potential for integrated farming in the tropics. www. wisedane. com

Q 4. Which of the following bacterium produces butyric acid? A. Acetobacter aceti B. Clostridium butylicum C. Lactobacillus D. None of these www. wisedane. com

ANSWER (B) EXPLANATION Ø Two clostridial species Clostridium acetobutylicum and "Clostridium butylicum, " have been used in or developed for solvent fermentation. Ø Unlike yeast, which can digest sugar only into alcohol and carbon dioxide, C. acetobutylicum and other Clostridia can digest whey, sugar, starch, cellulose and perhaps certain types of lignin, yielding butanol, propionic acid, ether, and glycerin. www. wisedane. com

Q 5. Which of the following is added to milk to curdle it or produce fermented milk products? A. Azotobacter B. Lactobacillus C. Rhizobium D. Clostridium www. wisedane. com

ANSWER (B) EXPLANATION Ø When L. lactis ssp. lactis is added to milk, the bacterium uses enzymes to produce energy molecules (ATP), from lactose. The by-product of ATP energy production is lactic acid. The lactic acid produced by the bacterium curdles the milk that then separates to form curds, which are used to produce cheese. Ø Other uses that have been reported for this bacterium include the production of pickled vegetables, beer or wine, some breads, and other fermented foodstuffs, such as soymilk kefir, buttermilk, and others. www. wisedane. com

Q 6. Which bacteria gives protection against gastric injury? A. Methanogens B. Lacto Bacillus C. Lacto Cocas D. Lacto Strepto www. wisedane. com

ANSWER (B) EXPLANATION Ø Small intestinal bacterial overgrowth (SIBO), also termed bacterial overgrowths, or small bowel bacterial overgrowth syndrome (SBBOS), is a disorder of excessive bacterial growth in the small intestine. Ø Unlike the colon (or large bowel), which is rich with bacteria, the small bowel usually has fewer than 10, 000 organisms per millilitre. Patients with bacterial overgrowth typically develop symptoms including nausea, bloating, vomiting, diarrhea, malnutrition, weight loss and malabsorption which is caused by a number of mechanisms. Ø Certain species of bacteria are more commonly found in aspirates of the jejunum taken from patients with bacterial overgrowth. The most common isolates are Escherichia coli, Streptococcus, Lactobacillus, Bacteroides, and Enterococcus species. www. wisedane. com

Q 7. Which micro-organism are useful in fermentation of idli and dosa ? A. Bacteria B. Protozua C. Fungus D. Virus www. wisedane. com

ANSWER (A) EXPLANATION Ø Fermentation of idli or dosa batter is carried out largely by lactic acid bacteria (not yeast as mentioned in your question), the same class of microorganisms that are found in 'curd. ' Ø The predominating bacteria in the relevant early stages of fermentation have been found to be the ‘heterofermentative’ type like Leuconostoc mesenteroides, which produce carbon dioxide in addition to lactic acid, the acid found in dahi. Ø Homofermentative lactic acid bacteria produce only lactic acid. During the later stages of fermentation, the type of dominating bacteria change, but by then the batter is probably too sour. www. wisedane. com

Q 8. Which is useful to remove the oily stains in laundry? A. Renin B. Protease C. Amaylase D. Lipase www. wisedane. com

ANSWER (D) EXPLANATION Five main laundry detergent enzymes include • Protease for protein stain removal • Amylase for starch stain removal • Lipase for grease/ oil removal • Mannanase for mannan-based stain removal • Pectin-degrading enzyme for fruit-based stain removal www. wisedane. com

Q 9. Which is useful to remove weeds in agriculture? A. Pesticides B. Weedicide C. Fungicide D. Insecticides www. wisedane. com

ANSWER (B) EXPLANATION Ø A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place". Examples commonly are plants unwanted in human-controlled settings, such as farm fields, gardens, lawns, and parks. Ø Weedicides are commonly called herbicides. They are chemicals which control weeds to enter the field and compete with the crops and hence, cause a direct effect on the crop. Some common herbicides are 2, 4 -D, Metachlor, Round-up (glyphosate), and Nitofen. www. wisedane. com

Q 10. Which organism is useful for bio fertiliser ? A. Glomus B. Cynobacteria C. Azospirillum D. All the above www. wisedane. com

ANSWER (D) EXPLANATION Sl. No. Groups Examples 1. Free-living Cyano bacteria , Azotobacter, Beijerinkia, Azoospirillum, Clostridium, Klebsiella, Anabaena, Nostoc, 2. Symbiotic Rhizobium, Frankia, Anabaena azollae, Glomus 3. Associative Symbiotic Azospirillum www. wisedane. com

Q 11. Which organic compound is useful to prepare Silage ? A. Vitamin B. Protien C. Lipid D. Carbohydrates www. wisedane. com

ANSWER (D) EXPLANATION Ø Silage is fermented, high-moisture stored fodder which can be fed to cattle, sheep and other such ruminants (cud-chewing animals) or used as a biofuel feedstock for anaerobic digesters. It is fermented and stored in a process called ensilage, ensiling or silaging, and is usually made from grass crops, including maize, sorghum or other cereals, using the entire green plant. Ø Silage undergoes anaerobic fermentation, which starts about 48 hours after the silo is filled, and converts sugars to acids. Fermentation is essentially complete after about two weeks. Ø Before anaerobic fermentation starts, there is an aerobic phase in which the trapped oxygen is consumed. The closeness with which the fodder is packed, determines the nature of the resulting silage by regulating the chemical reactions that occur in the stack. When closely packed, the supply of oxygen is limited; and the attendant acid fermentation brings about the decomposition of the carbohydrates present into acetic, butyric and lactic acids. www. wisedane. com

Q 12. Which microorganism is useful to obtain short chain fattyacids ? A. Saecharhomyces Cerrevisiae B. Azeto bacter aciti C. Clostridium butirycum D. Aspergillus niger www. wisedane. com

ANSWER (C) EXPLANATION Ø Butyric acid produced by Clostridium butirycum is found in milk, especially goat, sheep and buffalo milk, butter, parmesan cheese, and as a product of anaerobic fermentation. Ø Butyric acid is a fatty acid occurring in the form of esters in animal fats. The triglyceride of butyric acid makes up 3– 4% of butter. When butter goes rancid, butyric acid is liberated from the glyceride by hydrolysis, leading to the unpleasant odour. It is an important member of the fatty acid subgroup called shortchain fatty acids www. wisedane. com

Q 13. Which of the following is related with steroids? (a) Citric acid (b) Butyric acid (c) Acetic acid (d) Palmitic acid www. wisedane. com

ANSWER (C) EXPLANATION Ø Acetic acid is an antibiotic that treats infections caused by bacteria or fungus. Ø Hydrocortisone is a steroid. It reduces the actions of chemicals in the body that cause inflammation. Ø Acetic acid and hydrocortisone otic (for the ear) is a combination medicine used to treat infections in the ear canal, and to relieve the symptoms of redness, itching, or swelling. This medicine will not treat an inner ear infection (also called otitis media). www. wisedane. com

Q 14. Which of the following is used to prevent blood clotting in blood vessels? (a) Steriods (b) Cyclo sporin-A (c) Streptokinase (d) Statins www. wisedane. com

ANSWER (C) EXPLANATION Ø Streptokinase (SK) is an enzyme secreted by several species of streptococci that can bind activate human plasminogen. SK is used as an effective and inexpensive thrombolysis medication in some cases of myocardial infarction and pulmonary embolism. Ø Plasmin is produced in the blood to break down fibrin, the major constituent of blood thrombi, thereby dissolving clots once they have fulfilled their purpose of stopping bleeding. Extra production of plasmin caused by streptokinase breaks down unwanted blood clots, for example, in the lungs. www. wisedane. com

Q 15. Which of the following is to be used in production of swiss cheese ? (a) Monoscus Purpureus (b) Clostridium bacterium (c) Lacto Bacillus (d) Saccharhomyces Cerrevisiae www. wisedane. com

ANSWER (B) EXPLANATION Ø Butyric acid produced by Clostridium butirycum is found in milk, especially goat, sheep and buffalo milk, butter, parmesan cheese, and as a product of anaerobic fermentation. Ø Butyric acid is a fatty acid occurring in the form of esters in animal fats. The triglyceride of butyric acid makes up 3– 4% of butter. When butter goes rancid, butyric acid is liberated from the glyceride by hydrolysis, leading to the unpleasant odour. It is an important member of the fatty acid subgroup called short-chain fatty acids www. wisedane. com

Q 16. Which of the following is useful as a immunosuppressive agent in organ transplant ? A. Cyclosprin-C B. Cyclosporin-L C. Cyclosporin-A D. All the above www. wisedane. com

ANSWER (C) EXPLANATION Ø Cyclosporine A injection is given together with a steroid medicine to prevent the body from rejecting a transplanted organ (e. g. , kidney, liver, or heart). It belongs to a group of medicines known as immunosuppressive agents. Ø When a patient receives an organ transplant, the body's white blood cells will try to get rid of (reject) the transplanted organ. Cyclosporine works by suppressing the immune system to prevent the white blood cells from trying to get rid of the transplanted organ. www. wisedane. com

Q 17. Which bacteria is useful for purification of sewage treatment ? A. Heterotrophs B. Symbiont C. Free living D. Parasite www. wisedane. com

ANSWER (A) EXPLANATION Ø The activated sludge process is a process for treating sewage and industrial wastewaters using air and a biological floc composed of heterotrophic bacteria and protozoa. Ø In a sewage (or industrial wastewater) treatment plant, the activated sludge process is a biological process that can be used for one or several of the following purposes: oxidizing carbonaceous biological matter, oxidizing nitrogenous matter: mainly ammonium and nitrogen in biological matter, removing nutrients (nitrogen and phosphorus). www. wisedane. com

Q 18. Which bacterial group is useful in biogas production? A. Rhizobium B. Methanogens C. Argonotrocs D. Eubectaria www. wisedane. com

ANSWER (B) EXPLANATION Ø Methanogens are the only known microorganisms capable of methane production, making them of interest when investigating methane abatement strategies. A number of experiments have been conducted to study the methanogen population in the rumen of cattle and sheep, as well as the relationship that methanogens have with other microorganisms. Ø An average cow emits around 250 litres of methane per day. www. wisedane. com

Q 19. Which organism is useful to produce Riboflavin ? A. Arabia hossipae B. Saccharhomyces Cervisiae C. (a) & (b) both D. None of them www. wisedane. com

ANSWER (D) EXPLANATION Ø Riboflavin is a nutrient necessary for maintaining good health in humans and animals. It is also commonly refered to as vitamin B 2. Ø As a food additive, it is used as an deep yellow – orange – red food colouring. Note that “flavin” comes from the Latin word for yellow, “flavus”. Ø Industrially, it can be produced by a variety of biotechnologies using fungus or bacteria. Some types of bacteria (Bacillus subtilis) have actually been genetically modified to increase their riboflavin production. www. wisedane. com

Q 20. Which bacteria is present in the alimentary canal of herbivores ? A. Azetobactor B. Methanogens C. Azospirillium D. Bacillus www. wisedane. com

ANSWER (B) EXPLANATION Ø Methanogens are the only known microorganisms capable of methane production, making them of interest when investigating methane abatement strategies. A number of experiments have been conducted to study the methanogen population in the rumen of cattle and sheep, as well as the relationship that methanogens have with other microorganisms. Ø Enteric fermentation occurs in the gut of some animals, especially ruminants. In the rumen, anaerobic organisms, including methanogens, digest cellulose into forms nutritious to the animal. Without these microorganisms, animals such as cattle would not be able to consume grasses. The useful products of methanogenesis are absorbed by the gut, but methane is released from the animal mainly by belching. www. wisedane. com

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