Class 12th Biology – 10 Microbes in Human Welfare MCQs
An organism which helps in broad spectrum pathogenic control is ____.
Tricoderma are free living fungi which are found associated with a number of root systems and hence help in control of a variety of pathogenic organisms. The rest are all narrow spectrum biocontrol agents.
Farmers have reported over 50% higher yields of rice by using the biofertilizer
Farmers have reported over 50% higher yields of rice by using the biofertilizer Azolla.
Which one is wrongly matched?
Curd contains numerous lactic acid bacteria (LAB) or Lactobacillus. These bacteria produce acids (lactic acid) that coagulate and digest milk proteins.
Azospirillum can be used as biofertiliser because ____.
Azospirillum acts as biofertilisers because they can fix nitrogen and thus enrich the soil.
A bacteria which grows anaerobically on cellulosic material is ____.
A bacteria which grows anaerobically on cellulosic material is Methanobacterium. It grows anaerobically on plant material and helps in breakdown of cellulose.
Which one of the following is a wrong matching of a microbe and its industrial product, while the remaining three are correct?
Clostridium butyricum industrially produces butyric acid.
The common nitrogen fixer in paddy fields is
The common nitrogen fixer in paddy field is Azospirillum. It is an anaerobic bacteria that forms loose association with roots of paddy crops.
In developing countries, the heaviest demand from forests is for
Wood which is used as source of energy is called fuel wood and about 2 billions people in world are dependent upon wood as a source of fuel.
Activated sludge contains
Activated sludge contains masses of bacteria associated with fungal filaments. These are called bacterial flocs.
Which of the following is a photosynthetic nitrogen fixer?
Nostoc is an autotrophic nitrogen fixer.Rhizobium is symbiotic in nature.Aspergillus and Clostridium are not nitrogen fixers.
Which one of the following help in absorption of phosphorus from soil by plants?
Glomus aggregatum is a mycorrhizal fungus used as a soil inoculant in agriculture and horticulture. Its purpoae is to increase the surface area of roots for nutrient absorption like phosphorus.
In which stage of sewage treatment is biogas produced?
Bacteria that grow in the anaerobic sludge digester digest the bacterial flocs in the activated sludge to produce biogas.
An undistilled alcoholic beverage produced from grain fermentation is
Whisky and rum are distilled alcoholic beverages produced from grain fermentation. Wine is an undistilled alcoholic beverage produced by fermentation of fruit juices. Beer is a undistilled alcoholic beverage produced by fermentation of grains/cereals.
BOD is connected with
BOD is an index of both the microbes and organic matter present in water.
When yeast ferments glucose, the products formed are
Yeast fermentation yeilds ethanol and carbon dioxide.
When compared to milk, curd has
Lactic acid bacteria (LAB) help in converting milk to curd which improves the nutritional quality by increasing vitamin B 12.
Which of the following is not true for pesticides?
They are biodegradable is not true regarding pesticides. They are nonbiodegradable , synthetic chemicals which can cause biomagnification.They are broad spectrum chemicals and are not specific in their actions.
Which one thing is not true about antibiotics?
Each antibiotic is effective only against one particular kind of germ' is not correct.
Biofuels are
Biofuels are biological origin, which is a major source of energy. They are renewable and used properly and efficiently.
In biogas, methane is produced by the action of ____.
Methane is produced due to the action of methanogenic bacteria which belong to archaebacteria.
Which of the following is not a correct pair?
Clostridium butyricum produces butyric acid, and not benzoic acid.
Antibiotics can be used against
Antibiotics are not effective against viruses as its genetic material mutate to a greater extent. Also viruses do not have a true cellular structure ,they live inside a host cell,their structure and replication process is also different from bacteria.That is why antibiotics have difficulty in targeting them .However,they can stop the growth of both bacteria and fungi.
Biogas consists of
Biogas consists of carbon dioxide, methane and hydrogen.
In sewage treatment , primary treatment consists of
The primary treatment involves only physical removal of particles from sewage through filtration and sedimentation.
The coagulation of milk by LAB is because of conversion of
During growth, LAB produce lactic acid from the milk sugar (lactate). Lactic acid is responsible for coagulation of milk and partial digestion of milk proteins to form curd.
Cyanobacteria are important source of biofertiliser for which of these crops?
Cyanobacteria are nitogen fixers which are associated with aquatic ecosystems . Paddy crops are generally grown in water logged fields before transplantation and hence these bacteria serve as biofertilisers in these ecosystems.
Which one the following is a 'clot buster'?
Streptokinase obtained from Streptococcus bacteria helps in removing clots from the blood vessels of patients who have undergone myocardial infarction.
Escherichia coli is used as an indicator organism to determine pollution of water with
Escherichia coli is used as an indicator organism to determine pollution of water with faecal matter.
IPM does not involve the use of ____.
IPM does not involve the use of chemical method of pest control. Integrated pest control or IPM is a method of pest control which involves the use of biocontrol, mechanical control of pests and the use of a variety of crop cultivation methods like crop rotation for effective control of pests. It does not involve the use of synthetic chemicals like insecticides and pesticides for pest management.
Azotobacter is an example of
Azotobacter is an example of non-symbiotic, aerobic nitrogen fixer.
