Bottled fruit juices are often clearer than fresh juices due to the action of:
- Streptokinase
- Ligases
- Lipases
- Pectinases and Proteases
Explanation: Pectinases and proteases break down the plant cell wall components and proteins that cause cloudiness in juices.
The gas mixture produced in anaerobic sludge digesters, known as biogas, primarily contains:
- Nitrogen and Methane
- Methane and Oxygen
- CO2 and Ammonia
- Methane, H2S, CO2
Explanation: Anaerobic bacteria digest the sludge to produce a flammable mixture of gases, predominantly methane.
The primary treatment of sewage is basically a process of:
- Chemical oxidation
- Electrolytic removal
- Physical separation
- Biological digestion
Explanation: Primary treatment involves the physical removal of large and small particles from sewage through sequential filtration and sedimentation.
The full commercial potential of Penicillin as an effective antibiotic was established by:
- Selman Waksman
- Louis Pasteur
- Chain and Florey
- Alexander Fleming
Explanation: While Fleming discovered it, Ernest Chain and Howard Florey developed Penicillin into a powerful antibiotic used during WWII.
Alexander Fleming discovered Penicillin while working on which bacterium?
- Bacillus subtilis
- Streptococci
- Escherichia coli
- Staphylococci
Explanation: Fleming observed that a mold (Penicillium) inhibited the growth of Staphylococcus bacteria on his culture plates.
Which of the following is an example of a free-living nitrogen-fixing bacterium?
- Glomus
- Lactobacillus
- Azotobacter
- Rhizobium
Explanation: While Rhizobium is symbiotic, Azotobacter and Azospirillum are free-living bacteria that enrich soil nitrogen.
Acetobacter aceti is a bacterium primarily utilized for the production of:
- Citric acid
- Acetic acid
- Butyric acid
- Lactic acid
Explanation: Acetobacter aceti is an aerobic bacterium that converts ethanol into acetic acid (vinegar).
Primary treatment of sewage involves the removal of stable particles through:
- Chlorination
- Microbial digestion
- Filtration and Sedimentation
- Neutralization
Explanation: Primary treatment is a physical process that removes large and small particles through sequential filtration and sedimentation.
Which organic acid is industrially produced using the fungus Aspergillus niger?
- Lactic acid
- Butyric acid
- Acetic acid
- Citric acid
Explanation: Aspergillus niger is a fungus used for the large-scale industrial production of citric acid.
Baculoviruses are excellent candidates for Integrated Pest Management (IPM) because they are:
- Non-viral
- Toxic to humans
- Broad spectrum
- Species-specific
Explanation: Baculoviruses (Nucleopolyhedrovirus) are narrow-spectrum insecticidal applications that do not harm non-target organisms.
Methanogens are anaerobic bacteria that produce large amounts of methane along with:
- CO and H2O
- CO2 and H2
- SO2 and NO2
- O2 and N2
Explanation: Methanogenic bacteria produce a mixture of gases—primarily methane, carbon dioxide, and hydrogen—during the decomposition of organic matter.
The Ministry of Environment and Forests initiated which plans to save major Indian rivers from sewage pollution?
- Godavari/Krishna Plans
- Ganga/Yamuna Action Plans
- Narmada/Tapi Plans
- Indus/Sutlej Plans
Explanation: These action plans proposed the construction of a large number of sewage treatment plants (STPs) to prevent the discharge of untreated sewage into rivers.
Organic farming emphasizes the use of biocontrol agents over chemical pesticides to:
- Kill all insects
- Sterilize the soil
- Maintain biodiversity
- Lower crop yield
Explanation: Organic farmers believe in maintaining a balance within the ecosystem by managing pests rather than eradicating them, which protects beneficial organisms.
Which genus of fungi is most commonly associated with the formation of Mycorrhiza?
- Rhizobium
- Azotobacter
- Glomus
- Nostoc
Explanation: Many members of the genus Glomus form symbiotic mycorrhizal associations with plants.
In a paddy field, which of the following organisms serves as an important biofertilizer?
- Azotobacter
- Rhizobium
- Cyanobacteria
- Mycorrhiza
Explanation: Cyanobacteria (like Anabaena and Nostoc) are autotrophic microbes that fix atmospheric nitrogen and are particularly important in rice (paddy) cultivation.
Microbes like 'Methanobacterium' are essential in a biogas plant for the production of:
- Oxygen
- Chlorine
- Methane
- Nitrogen
Explanation: Methanobacterium is an anaerobic bacterium that breaks down cellulosic material in cow dung to produce methane-rich biogas.
Statins, used for lowering blood-cholesterol levels, are commercially produced by the yeast:
- Saccharomyces cerevisiae
- Trichoderma polysporum
- Candida albicans
- Monascus purpureus
Explanation: Statins act by competitively inhibiting the enzyme responsible for cholesterol synthesis in the liver.
Which of the following beverages is produced without the process of distillation?
Explanation: Wine and beer are produced by fermentation without distillation, whereas whisky, brandy, and rum are produced by distillation of the fermented broth.
Large-scale production of alcohol is achieved using which substrate with yeast?
- Raw wood
- Malted cereals
- Pure water
- Inorganic salts
Explanation: Brewer's yeast ferments the sugars found in malted cereals and fruit juices to produce ethanol.
What is the relationship between the BOD of a water body and its pollution level?
- Higher the BOD
- Lower the BOD
- BOD is constant
- No direct relation
Explanation: A high BOD indicates that the water is highly polluted with organic waste, as more oxygen is needed for decomposition.
Which microorganism is used to produce 'Statins' commercially?
- Aspergillus niger
- Trichoderma polysporum
- Monascus purpureus
- Acetobacter aceti
Explanation: Statins are blood-cholesterol-lowering agents produced commercially by the yeast Monascus purpureus.
Cyanobacteria such as Anabaena and Nostoc serve as important biofertilizers in:
- Paddy fields
- Corn fields
- Cotton fields
- Wheat fields
Explanation: Cyanobacteria are autotrophic microbes that fix atmospheric nitrogen and add organic matter to soil, particularly in rice paddies.
In sewage treatment, the term 'Flocs' refers to masses of:
- Viruses and Bacteria
- Bacteria and Fungi
- Bacteria and Protozoa
- Algae and Fungi
Explanation: Flocs are mesh-like structures formed by bacteria associated with fungal filaments during the secondary treatment of sewage.
The fungus Trichoderma polysporum is the industrial source for which bioactive molecule?
- Streptokinase
- Cyclosporin A
- Statins
- Citric acid
Explanation: Cyclosporin A is a powerful immunosuppressive agent used in organ transplant surgery to prevent the recipient's immune system from rejecting the new organ.
Which enzyme is added to detergents to assist in the removal of oily stains from laundry?
- Lipases
- Amylases
- Pectinases
- Proteases
Explanation: Lipases break down fats and oils, making them essential components in laundry detergent formulations.
Which microbial product is clinically used as a 'clot buster' for patients with myocardial infarction?
- Penicillin
- Streptokinase
- Cyclosporin A
- Statins
Explanation: Streptokinase, produced by the bacterium Streptococcus, is used to dissolve blood clots in patients suffering from heart attacks.
In the industrial production of antibiotics, large vessels used for microbial growth are called:
- Autoclaves
- Bioreactors
- Fermentors
- Incubators
Explanation: Large-scale production of industrial products like beverages and antibiotics requires growing microbes in very large vessels called fermentors.
The 'activated sludge' is allowed to sediment in a settling tank to produce:
- Secondary effluent
- Inoculum sludge
- Primary sludge
- Anaerobic gas
Explanation: A small part of the activated sludge (sedimented flocs) is pumped back into the aeration tank to serve as the 'starter' or inoculum.
The puffed-up appearance of bread dough is due to the production of CO2 gas by:
- Acetic bacteria
- Propionic bacteria
- Lactic bacteria
- Baker's yeast
Explanation: Saccharomyces cerevisiae (Baker's yeast) ferments sugars in the dough, releasing CO2 which causes the dough to rise or puff up.
Statins, used for lowering blood cholesterol, function by acting as a:
- Competitive inhibitor
- Clotting factor
- Digestive enzyme
- Hormone precursor
Explanation: Statins competitively inhibit the enzyme HMG-CoA reductase, which is responsible for the rate-limiting step in cholesterol synthesis.
Biochemical Oxygen Demand (BOD) is a measure of:
- Floating debris
- Industrial chemicals
- Dissolved salts
- Organic matter
Explanation: BOD measures the amount of oxygen required by bacteria to oxidize all the organic matter in a liter of water.
What happens to the BOD of sewage water after successful secondary treatment?
- Becomes zero
- Remains the same
- Increases significantly
- Decreases significantly
Explanation: Secondary treatment uses microbes to consume organic matter, which reduces the Biological Oxygen Demand (BOD) of the effluent before it is released.
Which microorganism is used as a biological control agent against butterfly caterpillars?
- Rhizobium
- Trichoderma
- Bacillus thuringiensis
- Baculoviruses
Explanation: The spores of Bacillus thuringiensis (Bt) produce a toxin that kills specific insect larvae when ingested.
Baculoviruses used as biocontrol agents belong to which specific genus?
- Glomus
- Nucleopolyhedrovirus
- Trichoderma
- Rhizobium
Explanation: Most baculoviruses used for pest control belong to the genus Nucleopolyhedrovirus and are known for their narrow-spectrum, species-specific insecticidal action.
The bacterium Clostridium butylicum is the industrial source of:
- Citric acid
- Acetic acid
- Lactic acid
- Butyric acid
Explanation: Clostridium butylicum is an anaerobic bacterium used for the production of butyric acid.
Mycorrhizal fungi provide the host plant with increased resistance to:
- Air pollution
- Direct sunlight
- Mechanical damage
- Root-borne pathogens
Explanation: Fungal symbionts in mycorrhiza protect the plant from root-borne pathogens, in addition to increasing tolerance to salinity and drought.
Which enzyme is used industrially to clarify bottled fruit juices?
- Lipases
- Streptokinase
- Pectinases
- Amylases
Explanation: Pectinases (often used with proteases) break down the pectins and proteins that cause cloudiness in fruit juices, making the bottled juice clear.
The large holes in 'Swiss Cheese' are produced due to the high production of CO2 by:
- Propionibacterium sharmanii
- Saccharomyces cerevisiae
- Lactobacillus bulgaricus
- Penicillium roqueforti
Explanation: Propionibacterium sharmanii is a bacterium that produces large amounts of carbon dioxide during fermentation, creating the characteristic holes in Swiss cheese.
Methanogens, such as Methanobacterium, are typically found in:
- Oceans
- Rumen of cattle
- Primary settling tanks
- Aeration tanks
Explanation: Methanogens are anaerobic bacteria found in the rumen of cattle where they help in the breakdown of cellulose.
The technology of biogas production in India was developed largely due to the efforts of:
- ISRO and DRDO
- ICMR and CSIR
- NITI Aayog
- IARI and KVIC
Explanation: The Indian Agricultural Research Institute (IARI) and the Khadi and Village Industries Commission (KVIC) spearheaded the development of biogas technology in India.
Secondary treatment of sewage is primarily a:
- Mechanical process
- Chemical process
- Biological process
- Physical process
Explanation: Secondary treatment involves using aerobic and anaerobic microbes to decompose the organic matter in the sewage effluent.
The 'starter' or inoculum added to fresh milk to convert it into curd contains millions of:
- LAB
- Molds
- Methanogens
- Yeasts
Explanation: Lactic Acid Bacteria (LAB) like Lactobacillus grow in milk and convert it to curd by digesting milk proteins and producing lactic acid.
A major component of biogas produced from cow dung (Gobar gas) is:
- Methane
- Ethane
- Butane
- Propane
Explanation: Biogas is typically 50-70% methane, produced by the action of methanogenic bacteria on cow dung.
The symbiotic nitrogen-fixing bacterium 'Rhizobium' is found in the root nodules of:
- Cereal plants
- Leguminous plants
- Citrus plants
- Coniferous plants
Explanation: Rhizobium forms a symbiotic relationship with the roots of legumes (like peas, beans, and lentils) to fix atmospheric nitrogen into ammonia.
Which of the following gases is NOT typically found in the biogas produced in a digester?
- Carbon dioxide
- Hydrogen sulfide
- Oxygen
- Methane
Explanation: Biogas is produced by anaerobic bacteria (methanogens); the presence of oxygen would inhibit their activity. Biogas mainly consists of CH4, CO2, and H2S.
In sewage treatment, the 'primary effluent' is passed into large aeration tanks for:
- Secondary treatment
- Chlorination
- Sludge drying
- Physical filtration
Explanation: Secondary treatment (biological treatment) involves passing the primary effluent into aeration tanks where aerobic microbes decompose the organic matter.
Which of the following is a biocontrol agent used to get rid of aphids and mosquitoes?
- Bees and Wasps
- Ladybird and Dragonflies
- Butterflies and Moths
- Caterpillars and Beetles
Explanation: The beetle with red and black markings (Ladybird) is used to control aphids, while dragonflies are used to control mosquitoes.
The fungal genus 'Glomus' is significant in agriculture because it forms:
- Flocs
- Nitrogen nodules
- Mycorrhiza
- Lichens
Explanation: Members of the genus Glomus form symbiotic associations with plant roots (Mycorrhiza), helping the plant absorb phosphorus and providing other benefits.
Which microorganism is commercially used as 'Brewer’s Yeast' for the production of ethanol?
- Aspergillus niger
- Saccharomyces cerevisiae
- Monascus purpureus
- Lactobacillus acidophilus
Explanation: Saccharomyces cerevisiae is widely used for fermenting malted cereals and fruit juices to produce ethanol in the beverage industry.
The immunosuppressive agent 'Cyclosporin A' is produced from the fungus:
- Aspergillus niger
- Trichoderma polysporum
- Penicillium notatum
- Monascus purpureus
Explanation: Cyclosporin A is a bioactive molecule used in organ-transplant patients to prevent graft rejection.
Microbes used as biofertilizers are preferred over chemical fertilizers because they:
- Kill all pests
- Pollute the air
- Are very expensive
- Enrich soil nutrients
Explanation: Biofertilizers are organisms that enrich the nutrient quality of the soil through nitrogen fixation and phosphorus solubilization.
Which of the following is a bioactive molecule that inhibits the enzyme responsible for cholesterol synthesis?
- Cyclosporin A
- Penicillin
- Streptokinase
- Statin
Explanation: Statins act as competitive inhibitors of the enzyme HMG-CoA reductase, which is essential for cholesterol production.
Which traditional drink of Southern India is made by fermenting sap from palms?
Explanation: Toddy is a traditional beverage in parts of Southern India made by fermenting the sugary sap collected from palm trees.
Which of the following is a 'bioactive molecule' that helps in organ transplant cases?
- Citric acid
- Statin
- Streptokinase
- Cyclosporin A
Explanation: Cyclosporin A is a bioactive molecule that suppresses the immune response, making it vital for patients undergoing organ transplants.
Which fungus is used as a common biocontrol agent for several plant pathogens in the root ecosystem?
- Glomus
- Aspergillus
- Trichoderma
- Monascus
Explanation: Trichoderma species are free-living fungi that are very effective biocontrol agents in the rhizosphere.
Which of the following is a 'clot buster' used to remove clots from the blood vessels?
- Cyclosporin A
- Statins
- Streptokinase
- Penicillin
Explanation: Streptokinase is an enzyme produced by the bacterium Streptococcus and modified by genetic engineering to dissolve blood clots in heart patients.
The symbiotic association between fungi and the roots of higher plants is called:
- Legume
- Mycorrhiza
- Lichen
- Floc
Explanation: Mycorrhiza is a symbiotic relationship where the fungus helps the plant absorb phosphorus and provide resistance to root-borne pathogens.
Lactic Acid Bacteria (LAB) improve the nutritional quality of curd by increasing the content of:
- Vitamin B12
- Vitamin D
- Vitamin A
- Vitamin C
Explanation: During the conversion of milk to curd, LAB increases the nutritional value by significantly increasing the concentration of Vitamin B12.
Roquefort cheese is ripened by growing a specific fungus on it to give it a particular:
- Unique flavor
- Large size
- Hard texture
- White color
Explanation: Roquefort cheese is ripened with the mold Penicillium roqueforti, which imparts a distinct blue-veined appearance and a sharp, characteristic flavor.
Which of the following is a 'free-living' nitrogen-fixing bacterium in the soil?
- Lactobacillus
- Rhizobium
- Glomus
- Azotobacter
Explanation: Unlike the symbiotic Rhizobium, Azotobacter and Azospirillum are free-living bacteria in the soil that can fix atmospheric nitrogen.