CBSE Class 12 Biology Microbes in Human Welfare MCQs Set F

Question: The chemical substances produced by some microbes which can kill or retard the growth of other microbes are called –
a) toddy
b) lactic acid
c) antibiotics
d) ethanol
Answer: c

Question: Biogas contains –
a) CO₂
b) H₂S
c) CH₄
d) all of these
Answer: d

Question: Streptomyces ramosus is the source of the antibiotic –
a) erythromycin
b) chloromycetin
c) aureomycin
d) terramycin
Answer: d

Question: Which of the following serve as biofertilizer in paddy fields?
a) Bacteria
b) Yeast
c) Cyanobacteria (blue-green algae)
d) Fungi
Answer: c

Question: Cyclosporin A is produced from –
a) Trichoderma polysporum (a fungus)
b) Bacillus (a bacterium)
c) Aspergillus (a fungus)
d) all of these
Answer: a

Question: During which stage of sewage treatment microbes are used?
a) Primary treatment
b) Secondary treatment
c) Tertiary treatment
d) All of these
Answer: b

Question: Which one of the following sets includes bacterial diseases?
a) Tetanus, tuberculosis, measles
b) Diphtheria, leprosy, plague
c) Cholera, typhoid, mumps
d) Malaria, mumps, poliomyelitis
Answer: b

Question: Usnic acid is an antibiotic obtained from –
a) Fungi
b) Bacteria
c) Lichens
d) Algal
Answer: c

Question: Streptomycin is produced from
a) Streptomyces scoleus
b) Streptomyces griseus
c) Streptomyces fradiae
d) Streptomyces venezuellae
Answer: b

Question: In gobar gas, the maximum amount is that of:
a) Butane
b) Methane
c) Propane
d) Carbon dioxide
Answer: b

Question: Statins used for lowering blood-cholesterol level are extracted from –
a) algae
b) bacteria
c) virus
d) Yeast
Answer: d

Question: Antibiotics are used to treat diseases like –
a) Plague
b) Whooping cough, Diphtheria
c) Leprosy
d) All
Answer: a

Question: Which of the following antibiotics was discovered first?
a) Streptomycin
b) Neomycin
c) Erythromycin
d) Penicillin
Answer: d

Question: The distillation of the fermented broth is required in the formation of
a) rum, beer, brandy
b) rum, brandy, whisky
c) beer, brandy, whisky
d) rum, beer, whisky
Answer: b

Question: The solids which settle after primary treatment of sewage are called
a) primary sludge
b) activated sludge
c) floes
d) total solids
Answer: a

Question: Which of the following bacteria help in nitrogen fixation from atmosphere?
A. Azotobacter B. Rhizobium C. Azospirillum D. Lactobacillus
a) A, C, D
b) A, B, C, D
c) B, C, D
d) A, B, C
Answer: d

Question: Acetic acid is produced by a
a) fungus
b) bacterium
c) Yeast
d) virus
Answer: b

Question: Ethyl alcohol is commercially manufactured from –
a) Bajra
b) Grapes
c) Maize
d) Sugarcane
Answer: d

Question: Which one(s) is/are correct about Cyclosporin A?
a) It is produced by the fungus Trichoderma polysporum
b) It is used as an immuno suppressive agent during organ transplantation
c) It is produced by a type of yeast, Monascus purpureus
d) Both a and b
Answer: d

Question: Which of the following is common to Azospirilium, Azotobacter, Anabaena, Nostoc and Oscillatoria?
a) Prokaryotes
b) N2-fixers
c) Both
d) Eukaryotes
Answer: b

Question: First hormone produced artificially by culturing bacteria is –
a) Insulin
b) Thyroxine
c) Testosterone
d) Adrenaline
Answer: a

Question: The mixture of gases released during anaerobic digestion of sludge is called
a) methane
b) carbon dioxide
c) biogas
d) flammable gases
Answer: c

Question: The advantage the fungi derive from mycorrhizal association with plants is –
a) Shelter + Nutrients
b) Water from soil
c) Minerals from soil
d) Tolerance to salinity
Answer: a

Question: Microbes are found –
a) in soil
b) in air
c) in water
d) everywhere
Answer: d

Question: Baculoviruses (Nucleopolyhedrovirus) does not show –
a) Host specificity
b) Narrow spectrum applications
c) Effects on non-target pathogens
d) Utility in IPM programme
Answer: c

Question: Which of the following bacteria has a role in removing clots from our blood vessels?
a) Bacillus thuringiensis
b) Clostridium butylicum
c) Streptococcus
d) Lactobacillus
Answer: c

Question: Consider the following statements (A-D) about organic farming :
a) Utilizes genetically modified crops like Bt cotton
b) Uses only naturally produced inputs like compost
c) Does not use pesticides and urea
d) Produces vegetables rich in vitamins and minerals
Which of the above statements are correct?
a) B, C and D
b) C and D only
c) B and C only
d) A and B only
Answer: c

Question: Yeasts have been used for the commercial production of
A. wine B. whisky C. ethanol D. curd
a) A, B, C
b) A, B, C, D
c) B, C, D
d) A, B, D
Answer: a

Question: I. All cyanobacteria are N2-fixers
II. The main sources of biofertilizers are bacteria, fungi and cyanobacteria’
III. Azospirilium and Azotobacter are symbiotic N2-fixers.
IV. Microbes like bacteria and many fungi can be grown on nutritive media to form colonies but they cannot be seen with the naked eyes.
a) All are correct
b) All are wrong
c) Only I, III and IV are wrong
d) Only II is wrong
Answer: c

Question: The technology of biogas production in India has been developed by the efforts of
A. Khadi and Village Industries Commision (KVIC)
B. Indian Council of Agricultural Research (IARI)
C. Indian Agricultural Research Institute (IARI)
D. Indian Council of Medical Research (!CMR)
a) A,C,D
b) C, D
c) A,C
d) A,B
Answer: c

Question: Microbes are present in –
A. Soil
B. Air
C. Water
D. Thermal springs
a) A, C,D
b) A, B, C, D
c) A, B
d) C,D
Answer: b

Question: Yeast is used in the production of
a) Citric acid and lactic acid
b) Lipase and pecinase
c) Bread and beer
d) Cheese and butter
Answer: c

Question: Which of the following food items is produced by fermentation by the microbes?
A. Idli
B. Dosa
C. Toddy
D. Cheese
a) A, B,C, D
b) C,D
c) A,C
d) A,B,C
Answer: a

Question: Which of the following cyanobacteria can fix atmospheric nitrogen?
A. Nostoc
B. Anabaena
C. Oscillatoria
D. Yeast
a) A,C, D
b) C,D
c) A,C
d) A,BC
Answer: d

Question: Which of the following is used as biofertilizer?
A. Cyanobacteria
B. Yeast
C. Symbiotic bacteria
D. Free living bacteria
a) A, B, C
b) A,B, D
c) A,C,D
d) A, B, D
Answer: c

Question: Methanogens grow anaerobically on cellulosic material and produce
A. methane
B. oxygen
C. carbon dioxide
D. hydrogen
a) A, C,D
b) A,B, C, D
c) B, C, D
d) A, B
Answer: a

Question: Microbes are diverse which include
A. Bacteria
B. Mosses
C. Protozoans
D. Fungi
a) A, C, D
b) A,D
c) A,B
d) C,D
Answer: a

Question:Symbiotic asociation is exhibited by
A. mycorrhiza. 
B. Rhizobium
C. heterocyst
D. Yeast
a) A, C, D
b) A, B, C, D
c) B, C, D
d) A, B
Answer: d

Question: Which industrial products are synthesized from microbes?
A. Antibiotics B. Fermented beverages C. Enzymes and chemicals D. Bioactive molecules
a) A, C, D
b) A, B, C, D
c) A, C
d) A, B, C
Answer: b

Question: Consider the following four statements (a-d) and select the option which includes all the correct ones only.
a) Single cell Spirulina can produce large quantities of food rich in protein, minerals, vitamins etc.
b) Body weight-wise the microorganism Methylophilus methylotrophus may be able to produce several times more proteins than the cows per day
c) Common button mushrooms are a very rich source of vitamin C
d) A rice variety has been developed which is very rich in calcium.
Options :
a) Statements (c), (d)
b) Statements (a), (c) and (d)
c) Statements (b), (c) and (d)
d) Statements (a), (b)
Answer: d

Question: Column 1                       Column II
I.Aspergillusniger                             A. Lactic acid
II. Lactobacillus                               B. Butyric acid
III. Clostridium butyl icum                C. Citric acid
IV. Trichoderma polysporum            D. CyclosporinA
Which of the combinations is correct?
    I II III IV
a) B A D C
b) C A B D
c) A B C D
d) D B A C
Answer: b

Question: Given below are three statements (A-C) each with or&\or more blanks. Select the option which correctly fills the blanks in the statements –
Statements:
A. _________ a traditional drink of some parts of South India is made by fermenting sap from palms.
B. Citric acid is obtained through the fermentation carried out by _______ and _______ on sugary syrups.
C. In ___________ the fungus forms a mantle on the surface of the roots.
Options:
a) A – Toddy; B – Aspergillus niger, Mucor, C – Ectomycorrhiza
b) A – Wine; B – Aspergillus niger, Mucor, C – Ectomycorrhiza
c) A – Beer; B – Aspergillus niger, Mucor, C – Ectomycorrhiza
Answer: a

Question: Given below are three statements (A-B) each with one or more blanks. Select the option which correctly fills the blanks in the statements –
Statements:
A Microbes consume the major part of the organic matter in the effluent and reduce _______ of sewage.
B. Certain bacteria which grow anaerobically on cellulosic material, produce large amount of methane along with C0₂ and H₂. The bacteria are commonly called as _______ and one such common bacterium is _______.
Options:
a) A – CO₂ demand; B – methanogens, Methanobacterium
b) A- Carbon; B -methanogens, Methanobacterium
c) A – biochemical oxygen demand; B – methanogens, Methanobacterium
d) A – biochemical oxygen demand; B – Methylokorus infernorum
Answer: c

Question: Given below are three statements (A-B) each with one or more blanks. Select the option which correctly fills blanks in the statements -Statements:
A. Statins produted by the yeast, _____
B. _______ contains insecticidalcrystal proteins thurioside, which is stomach poison and highly insect specific.
Options:
a) A – Monascus purpureus; B – Bacillus thuringiensis
b) A-Leuconostoccitrovorum;B-Mucorpusi1lus
c) A – Streptococcus thermophilus; B – Lactobacillus bulgaricus
d) A – Hordeum vulgare; B – Humulus lupulus
Answer: a

Question: Benefits of mycorrhizae are –
A. Resistance to root-borne pathogens B. Tolerance to s nity and absorption of phosphorus
C. Tolerance to drought
D. Overall increase in the plant growth and developme
a) Only A, B
b) Only B, C
c) Only C, D
d) A, B, C, D
Answer: d

Question: Given below are two statements (A-B) each with one or more blanks. Select the option which correctly fills the blanks in the statements-
Statements:
A. Terramycin is an antibiotic isolated from _____ and interfere with the _____ of disease causing bacteria.
B. Microorganisms (e.g., bacteria, yeast, filamentous fungi, algae, etc), that can be cultured on a commercial scale in fermenter and used as a.food source or as animal feed are called _______
Options:
a) A – Amanita, protein synthesis; B – single cell protein (SCP)
b) A – Penicillium, protein synthesis; B – single cell protein (SCP)
c) A – Morchella, protein synthesis; B – single cell protein (SCP)
d) A- Streptomyces rimosus, protein synthesis; B – single cell protein (SCP)
Answer: d

Question:Which of the following is correct?
I. Wine and beer are produced without distillation of fermented broth
II. Wine and beer are produced with distillation of fermented broth
III. Whisky brand and rum are produced by distillation of fermented broth
IV. Whisky brand and rum are produced without distillation of fermented broth
a) I and IV
b) I and III
c) llandV
d) II and III
Answer: b

Question: Column I Column II
I. Methanogens                          A. Microbial biocontrol agent
II. Organic wastes                      B. Penicillin
III. Bacillus thuringiensis            C. Biochemical oxygen demand
IV. Peuidiiiuni noisium                D. MethsnobactGrium
Which of the combinations is correct?
I II III IV
a) B A D C
b) C D A B
c) D C A B
d) D B A C
Answer: c