Class 12 Biology MCQs Chapter – 10
21. The symbiotic association between fungi and roots of higher plants is called :
( A ) Lichen
( B ) mycorrhiza
( C ) biofertilizer
( D ) biocontrol agent
Answer-( B )
22. Statins used for lowering blood-cholesterol level are extracted from:
( A ) algae
( B ) bacteria
( C ) viruses
( D ) yeasts
Answer-( D )
23. Which is the first step of sewage treatment
( A ) Precipitation
( B ) Chlorination
( C ) Sedimentation
( D ) Aeration
Answer-( C )
24. Integrated Pest management discourages the excessive use of :
( A ) biological methods
( B ) chemical pesticides
( C ) mechanical methods
( D ) All
Answer-( B )
25. Which in the following is a non- symbiotic biofertilizer?
( A ) VAM
( B ) Azotobacter
( C ) Anabaena
( D ) Rhizobium
Answer-( B )
26. Bacillus thuringiensis is used to control
( A ) bacterial pathogens
( B ) fungal pathogens
(C ) nematodes
( D) insect pests
Answer-( D )
27. Which is widely used successful biofertilizer in Indian rice fields ?
( A ) Rhizobium
( B ) Acacia
( C ) Acalypha
( D ) Azolla
Answer-( D )
28. N2-fixation in root nodules of almus is brought about by
( A ) Frankia
( B ) Azorhizobium
( C ) Bradyrhizobium
( D ) Clostridium
Answer-( A )
29. Name the fungus used for steroid synthesis ?
( A ) Aspergillus oryzae
( B ) Torulopsis utilis
( C ) Rhizopus stolonifer
( D ) Neurospora cross
Answer-( C )
30. A major component of gobar gas is :
( A ) butane
( B ) ammonia
( C ) methane
( D ) ethane
Answer-( C )
31. Baker’s yeast in the following is :
( A ) S.Cerevisae
( B ) S.ludwingia
( C ) S.Octosporus
( D ) Sehizosaccharomyces
Answer-( A )
32. ‘Yeast’ is an important source of :
( A ) Vitamin C
( B ) riboflavin
( C ) Sugars
( D ) Proteins
Answer-( B )
33. Formation of vinegar from alcohol is caused by :
( A ) Bacillus subtilis
( B ) Clostridium
( C ) Acetobacter aceti
( D ) Azotobacter
Answer-( C )
34. The bacterium capable of anaerobic N2-fixation is known as:
( A ) Azotobacter
( B ) Clostridium
( C ) Bacillus
( D ) Rhizobium
Answer-( B )
35. Brewery is connected with
( A ) Saccharomyces
( B ) Protozoans
( C ) Pteridophytes
( D ) Marsupials
Answer-( A )
36. For Nitrogen fixation in soil we may use
( A ) Cyanobacteria
( B ) Protozoans
( C ) Nematodes
( D ) Wheat plants
Answer-( A )
37. Which of the following antibiotics was extensively used to treat american soldiers wounded in world war II.
( A ) Neomycin
( B ) Bacitracin
( C ) Chloramphenicol
( D ) Penicillin
Answer-( D )
38. Probiotics are :
( A ) New kind of food allergens.
( B ) Safe antibiotics
( C ) Live microbial food supplement
( D ) Cancer inducing microbes
Answer-( C )
39. Organic farming does not include
( A ) green manures
( B ) chemical fertilizers
( C ) farmyard manures
( D ) compost
Answer-( B )
40. Farmers have reported 50% higher rice yield by the use of biofertilizers?
( A ) Bacillus thuringiensis
( B ) Rhizobium
( C ) Mycorrhizae
( D ) Azolla pinnata
Answer-( D )
