Tag: biofertilizers

Questions Related to biofertilizers

In Nostoc, the enzyme nitrogenase occurs in

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

  1. Vegetative cells

  2. Heterocysts

  3. Only in hormogones

  4. Both A and B

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Correct Option: B
Explanation:
Nostoc is a cyanobacteria. It has ability to fix atmospheric nitrogen. It converts nitrogen into ammonia. The heterocysts present in it are specialized cyanobacterial cells for nitrogen fixation. It contains enzyme nitrogenase. Nitrogenase is inactivated by oxygen. Hence, the heterocyst creates a micro anaerobic environment.
Thus, the correct answer is 'Heterocysts.'

The similarity between cyanobacterium and bacterium is

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

  1. Presence of flagella

  2. Presence of 80S ribosome

  3. Presence of nucleoid

  4. None of these

Show answer
Correct Option: C
Explanation:

There are many similarities between cyanobacterium and bacterium. They both posses saparophytic mode of life. They both lack true cell organelles. They both posses nucleoid instead of true nucleus. 

Thus, the correct answer is 'Presence of nucleoid.'

Pigment containing membranous extensions in some cyanobacteria are

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

  1. Chromatophores

  2. Heterocysts

  3. Basal bodies

  4. Penumatophores

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Correct Option: A

Members of which algal class impart red colour to red sea?

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

  1. Cyanophyceae

  2. Rhodophyceae

  3. Phaeophyceae

  4. Bacillariophyceae

Show answer
Correct Option: A
Explanation:

The red sea is the saltiest sea and connects to the ocean without any river meeting the sea. It is named so because of the abundant occurrence of red coloured planktonic cyanophyceae called Trichodesmium erythraeum. This cyanophyceae imparts red colour to red sea. This results in the algal bloom or red bloom.

Thus, the correct answer is 'Cyanophyceae.'

I. Unicellular, colonial, filamentous, marine or terrestrial forms.
II. The colonies are surrounded by a gelatinous sheath.
III. Some can fix atmospheric nitrogen in specialized cells called heterocysts.
IV. They often form blooms in water bodies.
These above characters are seen in

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

  1. Archaebacteria

  2. Cyanobacteria

  3. Chrysophytes

  4. Dinoflagellates

  5. Slime Moulds

Show answer
Correct Option: B
Explanation:

Cyanobacteria are also called as Blue green algae. They are unicellular, colonial, filamentous prokaryotes. They are found in marine and terrestrial habitats. The colonies are surrounded by a gelatinous sheath. They are photosynthetic bacteria. They often form blooms in water bodies and results in eutrophication. Some Cyanobacteria like Nostoc can fix atmospheric nitrogen in specialized cells called heterocysts and make it available to plants.

Thus, the correct answer is 'Cyanobacteria.'

Blue-green algae can be upto

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

  1. $10\mu$m long

  2. $50\mu$m long

  3. $25\mu$m long

  4. $500\mu$m long

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Correct Option: D

Azolla possesses symbiotic association with

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

  1. Anabaena

  2. Nostoc

  3. Azospirillum

  4. Rhizobium

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Correct Option: A

BGA is chiefly used as fertilizer in

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

  1. Wheat

  2. Paddy

  3. Mustard

  4. Gram

Show answer
Correct Option: B
Explanation:

BGA is chefly used as fertilizer in paddy fields for paddy crops.

Correct answer-B

A free living nitrogen fixing cyanobacterium which also forms symbiotic association with Azolla is?

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

  1. Anabaena

  2. Nostoc

  3. Chlorella

  4. Tolypothrix

Show answer
Correct Option: A
Explanation:

Azolla forms a symbiotic association with Anabaena for nitrogen fixation.

Correct answer-A

Which of the following is used as a green manure?

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

  1. Crotalaria juncea

  2. Azolla

  3. Hevea braziliensis

  4. Azadirachta juncea

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Correct Option: A