CBSE Questions for Class 12 Medical Biology Microbes In Human Welfare Quiz 6 - MCQExams.com

Fertility of paddy fields is improved by addition of
  • Rhizobium
  • Gypsum
  • Sodium sulphate
  • Blue-Green Algae
Ashbya gossypii  is a ________________.
  • Fungus producing riboflavin
  • Fungus forming $$B_{12}$$
  • Actinomycetes excreting Vitamin A
  • Bacterium forming antibodies
Antihaemorrhagic ergot alkaloids are got from _________.
  • Cinchona
  • Alga
  • Bryophyte
  • Fungus
Which is useful as biological control ?
  • Mucor mucedo
  • Trichoderma viridae
  • Penicillium notatum
  • Phytophthora parasitica
Yield of rice is increased by
  • Sesbania
  • Anabaena
  • Bacillus subtilis
  • B. popillae
Azolla is useful as green manure for
  • Wheat
  • Rice
  • Maize
  • Coconut
Methanogens growing anaerobically on cellulosic material produce
  • Methane
  • Methane and hydrogen
  • Methane and carbon dioxide
  • Methane, carbon dioxide and hydrogen
Azolla is used as a biofertilizer because it
  • Multiplies very fast to produce massive biomass
  • Has association of nitrogen-fixing Rhizobium
  • Has association of nitrogen-fixing cyanobacteria
  • Has association of mycorrhiza
Organic compound not decomposed by microbes in biogas plants is
  • Protein
  • Lignin
  • Cellulose
  • Phospholipid
The process that provides both energy and manure is
  • Burning of fuel wood
  • Pyrolysis of wood
  • Gasification of wood and wood shavings
  • Biogas formation
The technology of biogas production was developed in India through the efforts of
  • KVIC
  • IARI
  • Both A and B
  • WHO
pH favourable for fermentation in biogas plant is
  • $$4-5$$
  • $$5-6$$
  • $$6.8-7.2$$
  • $$7.6-8.4$$
Biogas production is rate limited by
  • Production of methane
  • Cellulose digestion
  • Conversion of monomers to organic acids
  • None of the above
During retting of jute fibres, the fermenting microbe is
  • Butyric acid bacteria
  • Streptococcus lactin
  • Helicobacter pylori
  • Methanophilic bacteria.
Temperature suitable for biogas production is
  • $$35^o-40^o$$C
  • $$20^o-25^o$$C
  • $$30^o-35^o$$C
  • $$40^o-44^o$$C
Primary treatment of sewage is
  • Physical process
  • Biological process
  • Chemical process
  • Biochemical process
Most active nitrogen fixing blue-green algae of rice fields is

  • Anabaena azollae

  • Aulosira fertilissima

  • Cylindrospermum licheniforme

  • Nostoc cycadacearum

A compound produced by an organism that inhibits the growth of another micro-organism is called
  • Antiseptic
  • Antibiotic
  • Anticoagulent
  • Antibodies
Cyclosporin A, used as immunosuppressive agent is obtained from

  • Bacterium Bacillus subtilis

  • Fungus Trichoderma polysporum

  • Fungus Tolypocladium inflatum

  • Both B and C
Which microorganism is employed in production of dextran?
  • Leuconostoc
  • Torulopsis
  • Rhizopus
  • Lactobacillus
Blood cholesterol lowering statins are obtained from

  • Streptococcus

  • Mucor javanicus

  • Monascus purpureus

  • Clostridium butyricum

BGA is chiefly used as fertilizer in
  • Wheat
  • Paddy
  • Mustard
  • Gram
Waksman got Nobel Prize for his discovery of
  • Penicillin
  • Neomycin
  • Chloromycetin
  • Streptomycin
Passage of effluents into oxidation tank is for
  • Primary treatment
  • Secondary treatment
  • Tertiary treatment
  • Both A and B
The fermenting agent of dosa and idli is
  • Saccharomyces cerevisiae
  • Leuconostoc mesenteroides
  • Streptococcus faecalis
  • Both B and C

Azolla possesses symbiotic association with

  • Anabaena

  • Nostoc

  • Azospirillum

  • Rhizobium

A third generation pesticide is
  • Pheromone
  • Weedicide
  • Juvenile hormone analogue
  • Both A and B
Streptomycin is prepared from ?

  • Streptomyces antibioticus

  • Streptomyces nodosus

  • Streptomyces griseus

  • Streptomyces rimosus

Thurioside is proteinaceous toxin obtained from
  • Biofertilizer
  • Green manure
  • Bacterial origin
  • Farmyard manure
Citric acid is obtained from _______

  • Aspergillus niger

  • Rhizobium nigricans

  • Penicillium citrinum

  • Lactobacillus vulgaricus

Yoghurt is produced with the help of

  • Lactobacillus bulgaricus

  • Lactobacillus thermophilus

  • Streptococcus thermophilus

  • Both A and C

Azolla is used as biofertilizer as it has

  • Rhizobium

  • Cyanobacteria
  • Mycorrhiza
  • Large quantity of humus
Which one is not used in the production of Yoghurt?
  • Streptococcus lactis
  • Streptococcus thermophilus
  • Lactobacillus bulgaricus
  • Acetobacter aceti
Aquatic fern which is an excellent biofertilizer is

  • Salvinia

  • Azolla

  • Marsilea

  • Pteridium

Which group is responsible for formation and flavour of yogurt?
  • Bacillus megathermus and Xanthomonas sp.
  • Bacillus subtilis and E.coli
  • Rhizobium meliloti and Azotobacter
  • Lactobacillus casei and Streptococcus thermophilus
Which of the following improves phosphorus uptake in plants?
  • Glomus
  • Rhizobium
  • Azospirillum
  • Azotobacter
What are used as green manure?
  • Melilotus parviflora
  • Lens esculenta
  • Crotalaria juncea
  • All the above
Lactic acid bacteria convert milk into curd and improves its nutritional quality by enhancing vitamin
  • A
  • B
  • C
  • D
Match the columns and choose the correct option.
Column IColumn II
(i)Aspergillus niger(a)Ethanol
(ii)Clostridium butylicum(b)Statins
(iii) Saccharomyces cerevisiae(c)Citric acid
(iv)Trichoderma polysporum(d)Butyric acid
(v)Monascus purpureus(e)Cyclosporin A
  • i-d, ii-c, iii-b, iv-a, v-c
  • i-e, ii-d, iii-a, iv-b, v-c
  • i-c, ii-d, iii-a, iv-e, v-b
  • i-c, ii-d, iii-e, iv-a, v-b
  • i-b, ii-c, iii-d, iv-e, v-a
Find out the pairs which are correctly matched.
aCyanobacteria$$1$$Biopesticide
bMycorrhiza$$2$$Solubilisation of phosphate
cBacillus thuringiensis$$3$$Cry protein
dSingle cell protein$$4$$Rhizobia
  • A and $$2$$
  • B and $$3$$
  • C and $$3$$
  • A and $$3$$
  • B and $$4$$
A free living nitrogen fixing cyanobacterium which also forms symbiotic association with Azolla is?
  • Anabaena
  • Nostoc
  • Chlorella
  • Tolypothrix
Which of the following is used as a green manure?
  • Crotalaria juncea
  • Azolla
  • Hevea braziliensis
  • Azadirachta juncea
Which proves to be effective biological control for nematodal pathogens of plants?
  • Pseudomonas cepacia
  • Pisolithus tinctorius
  • Gliocladium virens
  • Paecilomyces lilacinus
Which is not used as a biopesticide?
  • Xanthomonas campesteris
  • Bacillus thuringiensis
  • Trichoderma harzianum
  • Nucleo polyhedrosis virus
Select the correct statement from the following.
  • Methanobacterium is an aerobic bacterium found in rumen of cattle.
  • Biogas commonly called gobar gas is pure methane.
  • Activated sludge sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.
  • Biogas is produced by the activity of aerobic bacteria on animal waste.
The majority of Baculoviruses are used as biological control agents as.
  • They are species - specific
  • They have no negative impact on nontargets
  • Beneficial insects are being conserved
  • All the above
Which is a wrong match?
  • Yeast - statins
  • Acetobacter aceti - Acetic acid
  • Aspergillus niger - Citric acid
  • Clostridium butylicum - Lactic acid
Domestic sewage of large cities.
  • Has very high amount of suspended solids and dissolved salts
  • When treated in sewage treatment plant does not require aeration
  • Has high BOD as it contains both aerobic and anaerobic bacteria
  • Is processed by aerobic and then anaerobic bacteria in secondary treatment in sewage treatment plant
Secondary sewage treatment is mainly 
  • Chemical process
  • Mechanical process
  • Biological process
  • Physical process
Lactic acid bacteria grow in milk and convert it into curd increasing its nutritional value by increasing.
  • Vitamin A
  • Vitamin $$B_6$$
  • Vitamin $$B_{12}$$
  • Both A and C
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