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Q.1
Domestic sewage of large cities ...[ CBSE Mains2012]
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a) Has very high amount of suspended solids and dissolved salts
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b) When treated in sewage treatment plant does not requires aeration
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c) Has high BOD as it contains both aerobic and anaerobic bacteria
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d) Is processed by aerobic and then anaerobic bacteria in secondary treatment in sewage treatment plant
Explanation
Domestic sewage is first taken into a large primary settling tank where it undergoes sedimentation and screened organic matter constitute primary sludge. It is passed for secondary treatment. Primary sludge is passed into aeration tank where aerobic bacteria. The BOD falls to 10-15% of raw sewage. It undergoes sedimentation and the sediment is called activated sludge. Activated sludge is taken to anaerobic sludge digester. Here anaerobic microbes act upon organic matter to first produce monomers and then organic acids. Answer:(d)
Q.2
Confusion technique uses ,,, [ DPMT 2001]
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a) Pheromone
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b) Ecdysone
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c) Juvenile hormone
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d) A combination of hormones
Explanation
Confusion technique is will so that male insects cannot locate female. In this technique, small paper pieces having female pheromones are thrown over the area. Males will not be able to locate female. Answer:(a)
Q.3
Which of the following can use molecular nitrogen as nutrient? [ MPPMT 1998]
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a) Methanomonas
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b) Mucor
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c) Rhizobium
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d) Spirogyra
Explanation
Rhizobium form mutual beneficial association with root nodule of legumes. These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient. Answer:(c)
Q.4
Substrate for alcohol formation is ... [ BHU 2008]
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a) Sucrose
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b) Galactose
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c) Maize
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d) Bajra
Explanation
The traditional substrate for alcohol formation is sugar (cane or beet) or sugar-based byproducts such as molasses. Sugar and molasses are made of sucrose. Answer:(a)
Q.5
Antibiotic are drugs commonly used to cure ... [ JKCMEE 2000]
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a) Fungi
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b) Viruses
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c) Protozoans
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d) Bacteria
Explanation
Antibiotics is substance produced by microorganism which in low concentration inhibits the growth of pathogens without harming the host. Antibiotics cure bacterial disease Answer:(d)
Q.6
Which is correct about nitrogen fixation by legumes. They fix nitrogen through ... [ AFMC 1999]
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a) Specialised bacteria in their roots
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b) Specialised bacteria in their leaves
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c) Independent of bacteria that live in their roots
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d) The statement is wrong
Explanation
Root of legumes is in mutual beneficial association with Rhizobium. This association helps legumes fix atmospheric nitrogen to ammonia. Answer:(a)
Q.7
During sewage treatment, biogases are produced which include …[NEET 2013]
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a) Methane, hydrogensulphide, carbon dioxide
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b) Methane, oxygen, hydrogensulphide
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c) Hydrogensulphide, methane, sulphur dioxide
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d) Hydrogensulphide, nitrogen, methane
Explanation
Methane, CO2, H2S, H2. Answer:(a)
Q.8
Which of the following pesticides is an acetyl cholinestrase inhibitor ...[ CET Chd. 2011]
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a) Deltamethrin
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b) Permethrin
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c) Malathion
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d) DDT
Explanation
Pesticides mostly, exert toxicity by inhibiting the enzyme acetylcholinesterase (AChE) which degrades acetylcholine (ACh), an essential neurotransmitter in the central nervous system (CNS) of insects, rodents. Organophosphate pesticide produces these inhibitors. Deltamethrin is a pyrethroid ester insecticide. Deltamethrin plays a key role in controlling malaria vectors, and is used in the manufacture of long-lasting insecticidal mosquito nets; however, resistance of mosquitos and bed bugs to deltamethrin is becoming widespread. Permethrin is a broad spectrum, non-systemic, synthetic pyrethroid insecticide that targets adults and larvae of many species of biting, chewing, scaling, soil, and flying invertebrates Malathion is an organophosphate pesticide. Oxidative desulfuration converts malathion to malaoxon, which inhibits acetylcholinesterase in nervous tissues. Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Answer:(c)
Q.9
Rhizobium induced root nodules are internally pinkish due to ... [ MHTCET 2008]
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a) Xanthophyll
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b) Carotene
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c) Haemoglobin
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d) Leghaemoglobin
Explanation
Rhizobium induced root nodules has reddish pigment leghaemoglobin Answer:(d)
Q.10
Root nodules for nitrogen fixation of a non-leguminous tree possess ... [ BHU 1994]
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a) Azotobacter
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b) Thiobacillus
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c) Rhizobium
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d) Frankia
Explanation
Root nodules of non-legumes plants possess Frankia. Frankia can fix nitrogen in soil. Nodules produced by it do not have leghaemoglobin. Instead, they have hopanoids for O2 scavenging. Answer:(d)
Q.11
Lactic acid bacteria grow in milk and convert it into curd increasing its nutritional value by increasing ...[ AMU 2012]
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a) Vitamin A
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b) Vitamin B6
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c) Vitamin B12
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d) Both A and C
Explanation
Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it to curd. During growth, the LAB produce acids that coagulate and partially digest the milk proteins. A small amount of curd added to the fresh milk as inoculum or starter contain millions of LAB, which at suitable temperatures multiply, thus converting milk to curd, which also improves its nutritional quality by increasing vitamin B12. In our stomach too, the LAB play very beneficial role in checking disease causing microbes. Answer:(c)
Q.12
Bacillus thuringiensis is used to control ...[ DPMT 2010]
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a) Insect pests
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b) Nematodes
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c) Bacterial pathogens
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d) Fungal pathogens
Explanation
Bacteria Bacillus thuringiensis (often written as Bt) are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees, where these are eaten by the insect larvae. In the gut of the larvae, the toxin is released and the larvae get killed. The bacterial disease will kill the caterpillars, but leave other insects unharmed. Because of the development of methods of genetic engineering in the last decade or so, the scientists have introduced B. thuringiensis toxin genes into plants. Such plants are resistant to attack by insect pests. Answer:(a)
Q.13
The antibiotic inhibiting cell wall formation in bacterial cells is ...[ Odisha 2008]
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a) Clavicin
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b) Penicillin
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c) Ergotine
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d) None of the above
Explanation
Some antibiotics disrupts wall synthesis of bacterial cells. Example: penicillin, cephalosporins and bacitracin. Answer:(b)
Q.14
Continuous addition of sugar in 'fed batch' fermentation is done to ... [ CBSE 2011]
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a) Purify enzymes
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b) Degrade sewage
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c) Produce methane
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d) Obtain antibiotics
Explanation
A fed batch is a biotechnological batch process which is based on feeding of growth limiting nutrient substrate to a culture continuous addition of sugars in fed batch fermentation is done to purify enzymes. Fed-batch culture is the method in which "a base medium supports initial cell culture and a feed medium is added to prevent nutrient depletion. Sugar is added to purify the enymes. Answer:(a)
Q.15
Streptomycin is useful for treatment of pathogens ... [ MPPMT 1994]
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a) Gram (+)
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b) Gram (-)
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c) Both a and b
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d) Fram neutral
Explanation
Streptomycin has a broad spectrum of antibacterial activity. It is effective with respect to most Gram-negative and a few Gram-positive bacteria; staphylococci, streptococci, pneumococci, gonococci, meningococci, stimulus of dysentery, brucellosis, tuberculosis, rabbit fever, plague, and others. . It is used for various diseases caused by microorganisms that are sensitive to it in bacterial endocarditis, periotonitis, meningitis, infections of the urinary tract, gastric infections Answer:(c)
Q.16
The majority of Baculoviruses are used as biological control agents as ... [ HPPMT 2011]
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a) They are species-specific
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b) They have no negative impact on nontargets
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c) Beneficial insects are being conserved
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d) All the above
Explanation
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. . This is especially desirable when beneficial insects are being conserved to aid in an overall integrated pest management (IPM) programme, or when an ecologically sensitive area is being treated. Answer:(d)
Q.17
Leguminous plants are able to fix atmospheric nitrogen through symbiotic activity. Which is not correct?
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a) The enzyme nitrogenase catalyses the conversion of atmospheric nitrogen to ammonia
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b) Leghaemoglobin scavenges oxygen and is pinkish in colour
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c) Nodules act as sites for nitrogen fixation
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d) Nitrogenase is insensitive to oxygen
Explanation
Nodule of leguminous plants are in mutual beneficial association with Rhizobium. Nodule of root has reddish pigment called leghaemoglobin. Leghaemoglobin is an oxygen-carrying pigment, it decreases the free oxygen concentration in root nodules to maintain anaerobic conditions required for nitrogenase activity. Nitrogenase is sensitive to oxygen. The enzyme nitrogenase catalyses the conversion of atmospheric nitrogen to ammonia. Answer:(d)
Q.18
Yoghurt is produced with the help of ... [ MPPMT 2001]
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a) Lactobacillus bulgaricus
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b) Lactobacillus thermophilus
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c) Streptococcus thermophilus
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d) Both a and C
Explanation
Yogurt is a popular fermented dairy product produced by lactic acid bacteria, including Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. During yogurt production, these bacteria produce lactic acid, decreasing pH and causing milk protein to coagulate. Answer:(d)
Q.19
Leghaemoglobin takes part in ...[ Pb PMT 2007]
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a) Energy release
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b) N2 absorption
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c) Protecting nitrogenase from O2
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d) Supply of oxygen
Explanation
Leghaemoglobin is an oxygen-carrying pigment, it decreases the free oxygen concentration in root nodules to maintain anaerobic conditions required for nitrogenase activity. Answer:(c)
Q.20
Which is maintained for optimum production of vinegar ...[ Odisha 2008]
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a) Temperature at 65°C
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b) Aerobic condition
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c) Microaerophilic condition
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d) Anaerobic condition
Explanation
Vinegar is prepared ethanol. Ethanol from fermentation process is aerated and inoculated with Acetobacter aceti. The microbe produces acetic acid. When 10-13% of acetic acid content is achieved, the liquid is filtered. The liquid is allowed to ripen till the disagreeable smell disappears. It is pasteurized and called vinegar. C2H5OH + O2 → CH3COOH + H2O Answer:(b)
Q.21
Which one is correct ... [AIIMS 2011]
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a) Activated sludge is digested by anaerobic bacteria to produce marsh gas
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b) Aspergillus niger produces cyclosporin A
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c) Fleming, Chain and Florey were awarded Nobel Prize for discovering penicillin
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d) BOD is amount of oxygen produced by bacteria during decomposition
Explanation
Activated sludge is digested by anaerobic bacteria to first produce monomers and then organic acids. Methanogens then convert the latter into a mixture of gases like methane, hydrogen sulphide and carbon dioxide. The gaseous mixture is called biogas. Aspergillus niger produces citric acid. Biochemical oxygen demand (BOD) is the amount of dissolved oxygen (DO) needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. Answer:(c)
Q.22
Which is incorrect about fermentation ...
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a) Toddy is prepared by fermenting palm sap
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b) Propionibacterium is used in fermentation of cheese
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c) Pulled up appearance of dough is due to production of CO2
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d) Fermentation in muscles produces alcohol
Explanation
When we work our muscles hard, deficiency of oxygen lead to anaerobic respiration ( fermentation). Fermentation process in muscles produces lactic acid which makes our muscles fatigue and stiff. Answer:(d)
Q.23
Which one is an example of biocontrol of pests and pathogens using microbes ... [ CBSE 2012]
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a) Trichoderma against certain plant pathogens
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b) Bt cotton to increase cotton yield
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c) Lady bird beetle against aphids in Mustard
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d) Nucleopolyhedrovirus against white rust of Brassica
Explanation
A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma. Trichoderma species are free-living fungi that are very common in the root ecosystems.. They are effective biocontrol agents of several plant pathogens the ladybird beetle, C. septempunctata is well known as a good biological control agent because of predation in nature that has a short life cycle which is also a good character. . Thus, the above-mentioned species can be fruitfully used to minimize the sucking insect pests under mustard crop. In this case, microbes is not used. Answer:(a)
Q.24
Enzyme required for nitrogen fixation is ... [ CBSE 2001]
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a) Nitrogenase
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b) Nitroreductase
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c) Zymase
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d) Invertase
Explanation
Nitrogenases are enzymes that are produced by certain bacteria, such as cyanobacteria. These enzymes are responsible for the reduction of nitrogen to ammonia Answer:(a)
Q.25
Streptomyces griseus produces antibiotic ... [ CPMT 1991]
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a) Neomycin
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b) Streptomycin
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c) Chloramphenicol
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d) Terramycin
Explanation
Streptomyces griseus produces Streptomycin, which is a broad spectrum antibiotics. It is effective with respect to most Gram-negative and a few Gram-positive bacteria; staphylococci, streptococci, pneumococci, gonococci, meningococci, stimulus of dysentery, brucellosis, tuberculosis, rabbit fever, plague, and others. It is used for various diseases caused by microorganisms that are sensitive to it in bacterial endocarditis, periotonitis, meningitis, infections of the urinary tract, gastric infection. Answer:(b)
Q.26
Which of the following pairs of microbes can be grown on nutrient media ...[ HPPMT 2012]
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a) Viruses and single celled algae
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b) Protozoa and viroids
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c) Bacteria and fungi
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d) Prions and yeast
Explanation
Nutrient media is used to culture single cell protein (SCP). SCP is protein rich microbial biomass which can be used as food and feed. Microorganisms like algae, fungi, yeast, and bacteria have very high protein content in their biomass and are raised as single cell protein. Answer:(c)
Q.27
Which one is green manure/biofertilizer ..[ Wardha 2002]
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a) Sesbania
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b) Oat
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c) Rice
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d) Maize
Explanation
Green manure: It is ploughed back young leguminous crop like Sesbania aculeate, Sesbania rostrate (both root and stem nodules), Crotalaria juncea (Sunn hemp), Cyamopsis tetragonoloba, etc. Answer:(a)
Q.28
The product of which has been commercialised for lowering blood cholesterol ..[ AMU 2010]
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a) Trichoderma polysporum
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b) Aspergillus niger
0%
c) Saccharomyces cerevisiae
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d) Monascus purpureus
Explanation
Statins are inhibitors of enzymes required for cholesterol synthesis. Statins, therefore, lowers cholesterol level. They are produced from Yeast Monascus purpureus. Answer:(d)
Q.29
Antibiotics are mostly got from ... [ BHU 1999]
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a) Fungi
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b) Actinomycetes/Bacteria
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c) Both A and B
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d) Cyanobacteria
Explanation
Antibiotics are obtained from lichens, fungi, eubacteria and Actinomycetes. Answer:(c)
Q.30
rganic forming does not include
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a) Green manures
0%
b) Crop rotation
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c) Chemical fertilizer
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d) Compost and farmyard manures
Explanation
Organic farming is an agricultural system that uses fertilizers of organic origin such as compost manure, green manure, and bone meal and places emphasis on techniques such as crop rotation and companion planting. Biological pest control, mixed cropping and the fostering of insect predators are encouraged. Organic standards are designed to allow the use of naturally-occurring substances while prohibiting or strictly limiting synthetic substances. Answer:(c)
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