Tag: manuring

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

During rainy seasons, the ground becomes slippery due to dense growth of

  1. Lichens

  2. Bacteria

  3. Green algae

  4. Cyanobacteria
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Blue green algae or cyanobacteria synthesize a gelatinous mass around themselves, enclosing multiple filaments. This causes the surface area on which they thrive to be slippery

So, the correct answer is 'cyanobacteria'

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

Biofertilizers

  1. Kill pests

  2. Prevent pest growth

  3. Retain soil fertility

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Biofertilizers are used because they increase soil fertility, crop productivity, and production. Use of biofertilizers is both economical as well as environment-friendly. They remain symbiotically associated with the roots while some are free living. They solubilize the undissolved minerals.

So, the correct answer is option C.

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

True nucleus and mitochondria are absent in

  1. Cyanophyceae

  2. Chlorophyceae

  3. Myxomycetes

  4. Azolla
Reveal answer Fill a bubble to check yourself
A Correct answer
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.'

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

Which one of the following can fix nitrogen?

  1. Vaucheria

  2. Spirogyra

  3. Nostoc

  4. Ectocarpus
Reveal answer Fill a bubble to check yourself
C Correct answer
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.'
Multiple choice zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

Some blue green algae are used as biofertilizers because they

  1. Are photosynthetic

  2. Have mucilage

  3. Grow everywhere

  4. Fix nitrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
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.'
Multiple choice zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

Blue green algae are

  1. Actinomycetes

  2. Eukaryotes

  3. Prokaryotes

  4. Acellular
Reveal answer Fill a bubble to check yourself
C Correct answer
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.'

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

Aquatic fern which is an excellent biofertilizer is

  1. <p>Salvinia</p>

  2. <p>Azolla</p>

  3. <p>Marsilea</p>

  4. <p>Pteridium</p>
Reveal answer Fill a bubble to check yourself
B Correct answer
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'

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

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

  1. <p>Anabaena azollae</p>

  2. <p>Aulosira fertilissima</p>

  3. <p>Cylindrospermum licheniforme</p>

  4. <p>Nostoc cycadacearum</p>
Reveal answer Fill a bubble to check yourself
B Correct answer
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.