Tag: zoology

Questions Related to zoology

True nucleus and mitochondria are absent in

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

  1. Cyanophyceae

  2. Chlorophyceae

  3. Myxomycetes

  4. Azolla

Show answer
Correct Option: A
Explanation:

Prokaryotes are unicellular organisms. They lack membrane-bound organelles like mitochondria, golgi apparatus. They also lack true nucleus. Instead, they have nucleoid or incipient nucleus. Nucleoid is an undifferetiated, unorganised, fibrillar nucleus without any limiting membrane. They have ribosomes in the cytoplasm. Examples include bacteria, Cyanophyceae. 

Thus, the correct answer is 'Cyanophyceae.'

Which one of the following can fix nitrogen?

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

  1. Vaucheria

  2. Spirogyra

  3. Nostoc

  4. Ectocarpus

Show answer
Correct Option: C
Explanation:
The atmospheric nitrogen is not available to plants. There are some nitrogen-fixing bacteria which converts atmospheric nitrogen into ammonia which is readily available to plants. Nostoc is a cyanobacterium. It has the ability to fix atmospheric nitrogen. The heterocysts present in it contains nitrogenase enzyme. These are specialized for nitrogen fixation. 
Thus, the correct answer is 'Nostoc.'

Some blue green algae are used as biofertilizers because they

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

  1. Are photosynthetic

  2. Have mucilage

  3. Grow everywhere

  4. Fix nitrogen

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Correct Option: D
Explanation:
The atmospheric nitrogen is not available to plants. There are some nitrogen fixing bacteria which converts atmospheric nitrogen into ammonia which is readily available to plants. Some blue green algae like Anabaena and Nostoc have the ability to fix the atmospheric nitrogen. They are free-living nitrogen fixing bacteria. Hence, they are used as biofertilizers in the field of rice. 
Thus, the correct answer is 'Fix nitrogen.'

Blue green algae are

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

  1. Actinomycetes

  2. Eukaryotes

  3. Prokaryotes

  4. Acellular

Show answer
Correct Option: C
Explanation:

Prokaryotes are unicellular organisms without membrane-bound organelles like mitochondria, golgi complex. They lack true nucleus. Instead, they have nucleoid, genetic material without nuclear envelope. The examples of prokaryotes include bacteria, Cyanobacteria (Blue green algae). Blue green algae are photosynthetic bacteria.

Thus, the correct answer is 'Prokaryotes.'

Aquatic fern which is an excellent biofertilizer is

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

  1. Salvinia

  2. Azolla

  3. Marsilea

  4. Pteridium

Show answer
Correct Option: B
Explanation:

Biofertilizers are organisms that enrich the nutrient quality of the soil. The main source of biofertilizers are bacteria, fungus, and cyanobacteria. Symbiotic cyanobacteria Anabaena azollae fixes nitrogen in the leaves of Azolla ( aquatic fern ). Azolla pinnata ( a pteridophyte ) is used as an excellent biofertilizer in the rice field. 

So, the correct answer is 'Azolla'

Most active nitrogen fixing blue-green algae of rice fields is

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

  1. Anabaena azollae

  2. Aulosira fertilissima

  3. Cylindrospermum licheniforme

  4. Nostoc cycadacearum

Show answer
Correct Option: B
Explanation:

Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen. In paddy fields, cyanobacteria serve as an important biofertilizer. 

Aulosira fertilissima is the most active non-symbiotic nitrogen fixer in rice field in India. Hence, Option B is correct.

Which of the following act as a biofertilizers?

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

  1. Blue-green algae

  2. Green algae

  3. Yellow algae

  4. Red algae

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Correct Option: A

Which of the following microorganisms is used as a biofertilizer?

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

  1. Bacillus

  2. Azospirillum

  3. Pseudomonas

  4. Saccharomyces

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Correct Option: B

A fern commonly inoculated to paddy fields is

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

  1. Azolla

  2. Marsilea

  3. Salvinia

  4. Anabaena

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Correct Option: A

In paddy fields, biological nitrogen fixation is chiefly brought about by.

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

  1. Cyanobacteria

  2. Green algae

  3. Mycorrhiza

  4. Rhizobium

Show answer
Correct Option: A
Explanation:

In paddy fields,biological nitrogen fixation is brought about by Cyanobacteria(Nostoc, Anabaena).

Correct answer-A