Tag: microbes as biocontrol agents and biofertilizers

Questions Related to microbes as biocontrol agents and biofertilizers

Which one of the following is not a nitrogen-fixing organism ?

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. Anabaena

  2. Nostoc

  3. Azotobacter

  4. Pseudomonas

Show answer
Correct Option: D
Explanation:
Anabaena, Nostoc and Azolobacter help in nitrogen fixation. But Pseudomonas perform Denitrification which is the reduction of nitrates back into Nitrogen gas.
So, the correct option is 'Pseudomonas'

Which of the following statements is/are incorrect ?
(i) Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial habitats.
(ii) Anabaena, Nostoc and Oscillatoria are photosynthetic $N _2$ - fixing cyanobacteria.
(iii) Tolypothrix (BGA) can increase rice production by about 20%.
(iv) BGA add organic matter to the soil and increase its fertility.
(v) In our country, fertilizers are not available commercially in the markets for farmers.

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. (v) Only

  2. (iv) Only

  3. (iii) Only

  4. None of these

Show answer
Correct Option: A
Explanation:

Biofertilizers are available commercially in our country for farmers.

So, the correct option is '(v) Only'

Which of the following is widely used as a successful biofertiliser in Indian rice fields?

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. Rhizobium

  2. Acacia arabica

  3. Acalypha Indica

  4. Azolla pinnata

Show answer
Correct Option: D
Explanation:

Azolla pinnate is a small free-floating freshwater fern which is widely used as a biofertiliser in Indian rice fields. So, the correct answer is D.

Which one of the following microorganisms forms a symbiotic association with plants and helps them in their nutrition?

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. Glomus

  2. Azotobacter

  3. Klebsielfa

  4. Azospirillium

Show answer
Correct Option: A
Explanation:

Several fungi are known to form symbiotic associations with plants, i.e., mycorrhiza. The most common fungal partners of mycorrhiza are Glomus species.

Study the following statements and select the correct ones.


(i) Methanogens are archaebacteria that produce methane in marshy areas.
(ii) Nostoc is a filamentous blue-green alga which fixes atmospheric nitrogen.
(iii) Many members of the genus Glomus form mycorrhiza.

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. (i) and (ii)

  2. (i) and (iii)

  3. (ii) and (iii)

  4. (i), (ii) and (iii)

Show answer
Correct Option: C
Explanation:
1. Methanogens are archaebacteria belong to the domain of archaea, commonly found in wet, marshy areas,  They produce methane gas.
2. Nostoc is the filamentous blue-green alga. They form gelatin body which contains trichomes.
3. Glomus and it's all species form symbiotic relationships (mycorrhizas) with plant roots. 
So the correct answer is option D.

Which of the following statements is/are correct ?

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. In paddy fields, cyanobacteria serve as an important biofertiliser.

  2. Vermicompost consists of organic matter prepared by the action of earthworms on human or animal waste.

  3. The important examples of cyanobacteria as biofertilisers are Anabaena, Nostoc and Oscoilatoria.

  4. All of these

Show answer
Correct Option: B

Which of the following options includes biofertilisers ?

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. Cowdung manure and farmyard waste

  2. A quick growing crop ploughed back into the field

  3. Nostoc, Oscillatoria

  4. All of these

Show answer
Correct Option: A

Which was the first photosynthetic organism?

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. Green algae

  2. Red algae

  3. Cyanobacteria

  4. Brown algae

Show answer
Correct Option: C
Explanation:

Photosynthesis is the process by which light energy from the sun is used to synthesise sugars from carbon dioxide, releasing oxygen as a waste product. In primitive days, cyanobacteria were only the primary producers because the redox structure of oceans favoured them to fix nitrogen and also they had the capacity to use water as the source of electrons in photosynthesis. They made the atmosphere oxygen rich and allowed the appearance of aerobic organisms. 

Thus, the correct answer is option C.

Which one of the followings is not the characteristic feature of cyanobacteria?

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. They are always multicellular.

  2. They form colonies.

  3. They form blooms in polluted water bodies.

  4. They can fix atmospheric nitrogen.

Show answer
Correct Option: A
Explanation:

Cyanobacteria are unicellular prokaryotes that photosynthesise. They form huge colonies that appear as algal bloom in polluted waters. They can fix nitrogen from the atmosphere by means of specialised structures called as heterocysts.

Cow dung is appropriately used as

zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

  1. Manure

  2. Perfume

  3. Medicine

  4. Building material

Show answer
Correct Option: A
Explanation:

Cow dung is available in plenty in India. It is used as manure or pattings for fuel. The cow dung solution has antifungal and insecticide properties. The application of cow dung also improves soil salinity and alkalinity. The presence of this manure helps in better nitrogen fixation through rhizobia.

So, the correct answer is option A.