Nitrifying bacteria
convert free nitrogen to nitrogen compounds
convert proteins into ammonia
reduce nitrates to free nitrogen
reduce nitrates to free nitrogen
Which one of the following is an example of carrying out biological control of pests/diseases using microbes?
Trichoderma sp. against certain plant pathgens
Nucleopolyhedrovirus against white rust in Brassica
Bt-cotton to increase cotton yield
Bt-cotton to increase cotton yield
Which of the followings is mainly produced by the activity of anaerobic bacteria on sewage?
Propane
Mustard gas
Marsh gas
Marsh gas
What gases are produced in anaerobic sludge digesters?
Methane and CO2 only
Methane hydrogen sulphide and CO2
Methane, hydrogen sulphide and O2
Methane, hydrogen sulphide and O2
Where do certain symbiotic microorganisms normally occur in human body?
Caecum
Oral lining and tongue surface
Vermiform appendix and rectum
Vermiform appendix and rectum
A nitrogen-fixing microbe associated with Azolla in rice field is
Spirulina
Anabaena
Frankia
Frankia
Which of the following helps in absorption of phosphorus from the soil by plants?
Rhizobium
Frankia
Anabaena
Anabaena
Secondary sewage treatment is mainly a
mechanical process
chemical process
biological process
biological process
Consider the following four statements (a–d) and select the option which includes all the correct ones only:
Single cell Spirulina can produce large quantities of food rich in protein, minerals, vitamins etc.
Body weight-wise the microorganism Methylophilus methylotrophus may be able to produce several times more proteins than the cows per day.
Common button mushrooms are a very rich source of vitamin C.
A rice variety has been developed which is very rich in calcium.
Statements (III), (IV)
Statements (I), (III) and (IV)
Statements (II), (III) and (IV)
Statements (II), (III) and (IV)
