Microbes in Human Welfare

NEET Biology · 80 questions · Page 8 of 8 · Click an option or "Show Solution" to reveal answer

Q71

Which one of the following pairs is not correctly matched?

A Spirulina - Single cell protein

B Streptomyces - Antibiotic

C Rhizobium - Biofertilizer

D Serratia - Drug addiction

Correct Answer

Option D

Solution

Serratia marcescens is a harmful human pathogen causing UTIs, wound infections and pneumonia.

It is not linked to drug addiction.

Q72

The most thoroughly studied of the known bacteria-plant interactions is:

A Nodulation of Sesbania stems by nitrogen fixing bacteria

B Cyanobacterial symbiosis with some aquatic ferns

C Plant growth stimulation by phosphate-solubilising bacteria

D Gall formation on certain angiosperms by Agrobacterium

Correct Answer

Option D

Solution

Agrobacterium tumefaciens causes crown gall disease, one of the most studied bacteria-plant interactions.

It transfers Ti plasmid DNA to plant cells.

Q73

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

A Lignin

B Cellulose

C Hemi-cellulose

D Lipids

Correct Answer

Option A

Solution

Lignin is a complex polymer of phenylpropane units cross-linked with various chemical bonds.

It is resistant to anaerobic degradation.

Q74

Maximum application of animal cell culture technology today is in the production of:

A Interferons

B Vaccines

C Edible proteins

D Insulin

Correct Answer

Option B

Solution

Maximum application of animal cell culture technology is in the production of vaccines for viral diseases like hepatitis-B, rabies, polio and smallpox.

Q75

Which bacteria is utilized in gobar gas plant?

A Nitrifying bacteria

B Methanogens

C Ammonifying bacteria

D Denitrifying bacteria

Correct Answer

Option B

Solution

Methanobacillus (methanogen) occurs in marshes and dung.

It produces CH4 gas under anaerobic conditions and is utilized in gobar gas plants.

Q76

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

A Protozoans

B Bacteria

C Yeast

D Virus

Correct Answer

Option C

Solution

Yeast carry out fermentation, releasing CO2 making bread soft and porous. Saccharomyces is referred to as baker's yeast.

Q77

Which of the following is a true pair of biofertilizers?

A Nostoc and legume

B Rhizobium and grasses

C Salmonella and E. coli

D Azolla and BGA

Correct Answer

Option D

Solution

Azolla and blue-green algae Anabaena form biofertilizer in rice fields.

Q78

Which aquatic fern is used to increase the yield in paddy crop?

A Salvinia

B Isoetes

C Marsilea

D Azolla

Correct Answer

Option D

Solution

Azolla and its nitrogen-fixing partner Anabaena have been used as green manure to fertilise rice paddies and increase production.

Q79

Which of the following is used to manufacture ethanol from starch?

A Saccharomyces

B Lactobacillus

C Azotobacter

D Penicillium

Correct Answer

Option A

Solution

Yeast (Saccharomyces) helps in ethyl alcohol formation from starch via fermentation.

Q80

Which one of the following pairs is not correctly matched?

A Spirulina - Single cell protein

B Streptomyces - Antibiotic

C Rhizobium - Biofertilizer

D Aspergillus - Vinegar

Correct Answer

Option D

Solution

Vinegar (acetic acid) is produced by Acetobacter aceti, not Aspergillus. Aspergillus niger produces citric acid.

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