Tag: microbes as biocontrol agents and biofertilizers

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

Blue green algae used in rice fields to increase fertility is

  1. Rivularia

  2. Nostoc

  3. Aulosira

  4. Anabaena
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Blue Green Algae (BGA) is a good alternative source of nitrogen in rice fields to increase the soil fertility. Various BGA like Nostoc, Anabaena, Aulosira Scytonema are used to increase rice production. Out of all these, Aulosira fertilissima are most commonly used in rice fields.

Thus, the correct answer is 'Aulosira.'

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

If wheat field is inoculated with Rhizobium, then

  1. Soil will become nitrogen rich

  2. No effect on soil nitrogen

  3. Soil will be depleted of nitrogen

  4. Soil will become rich in calcium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Rhizobium is an important symbiont for legumes but it plays an important role with nonlegumes by producing growth hormones. When wheat is inoculated with Rhizobium, no effects are observed in terms of growth and yield, which indicates that uptake of soil nitrogen is not seen as in legumes.

So, the correct answer is option B.

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

How many feature/s are related to heterocyst ?
1) Has no cell wall
2) Contains nitrogenase enzyme 
3) Promotes fragmentation
4) Can be seen in Nostoc
5) Possesses PS II

  1. 5

  2. 3

  3. 2

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

Heterocyst is a specialized nitrogen=fixing cell found in some filamentous cyanobacteria like Nostoc, Anabaena. It has cell wall which is made up of three layers. It carries carries out nitrogen fixation. It is formed due to lack of fixed nitrogen. It fixes nitrogen under aerobic conditions. It contains nif gens and synthesize nitrogenase enzyme. Apart from nitrogenase enzymes, it also contains other enzymes required for nitrogen fixation. It promotes vegetative reproduction by filament fragmentation. It does not possesses PS II and hence cannot produce oxygen.

Thus, the correct answer is option B.

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

Identify the correct statement.

  1. Diatoms produce basidiospores

  2. Heterocysts occur in Nostoc

  3. Fronds develop in bryophytes

  4. Multiciliate sperms occur in angiosperms
Reveal answer Fill a bubble to check yourself
B Correct answer
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 occur in Nostoc.'