Microbes in Human Welfare

A free living nitrogen-fixing cyanobacterium which can also form symbiotic association with the water fern Azolla is

1. Tolypothrix
2. Chlorella
3. Nostoc
4. Anabaena

Dough kept overnight in warm weather becomes soft and spongy because of :-

1. Cohesion
2. Absorption of carbon dioxide from atmosphere
3. Osmosis
4. Fermentation

Which one of the following pairs is not correctly matched ?

1. Spirulina – Single cell protein
2. Streptomyces – Antibiotic
3. Rhizobium – Biofertilizer
4. Serratia – Drug addiction

A major component of gobar gas is

1. ethane
2. methane
3. butane
4. ammonia

Which of the following plants are used as green manure in crop fields and in sandy soils ?

1. Calotropis procera and Phyllanthus niruri
2. Dichanthium annulatum and Azolla nilotica
3. Saccharum munja and Lantana camara
4. Crotalaria juncea and Alhagi camelorum

During anaerobic digestion of organic waste, such as in producing biogas, which one of the following is left undegraded :-

1. Lignin
2. Cellulose
3. Hemi-cellulose
4. Lipids

Which bacteria is utilized in Gobar gas plant ?

1. Nitrifying bacteria
2. Methanogens
3. Ammonifying bacteria
4. Denitrifying bacteria

During the formation of bread it becomes porous due to release of CO2 by the action of : -

1. Protozoans
2. Bacteria
3. Yeast
4. Virus

Which of the following is a true pair of biofertilizers?

1. Nostoc and legume
2. Rhizobium and grasses
3. Salmonella and E. coli
4. Azolla and BGA

Which aquatic fern performs nitrogen fixation?

1. Azolla
2. Nostoc
3. Salvia
4. Salvinia