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

Cyanobacteria are commonly called blue-green algae. This is because they possess in addition to chlorophylls a blue pigment called

  1. Phycoerythrin

  2. Cyanophycin

  3. Phycocyanin

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phycocyanin Antioxidant. Phycocyanin is the main component in Linablue Spirulina Extract. It is a blue pigment that is important in the photosynthesis (food production) of cyanobacteria. It assists the function of chlorophyll, especially during low light conditions. So, the correct option is "C" (Phycocyanin).

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

Heterocysts are considered as a site of nitrogen fixation in nitrogen-fixing BGA as they possess

  1. RuBISCO

  2. PEP carboxylase

  3. Nitrogenase

  4. Zymase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Heterocysts are specialized nitrogen fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc punctitorme, Cylindrospermum stagnale and Anabaena sphaerica. They fix nitrogen from dinitrogen in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis.
So, the correct answer in 'Nitrogenase'.
Multiple choice zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

Nostoc is known to do

  1. Photosynthesis
  2. Photosynthesis and $N _2$ fixation simultaneously
  3. $N _2$ fixation only
  4. Either photosynthesis or $N _2$ fixation at a time
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nostoc is a genus of blue green algae. It is photosynthetic cyanobacteria. It contains chlorophyll pigment and carries out photosynthesis. It also has ability to fix atmospheric nitrogen and make it available to the plants. It is a non-symbiotic nitrogen fixer.

Thus, the correct answer is 'Photosynthesis and N$ _2$ fixation simultaneously.'

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

The monerans with heterocysts and oxygenic photosynthesis are

  1. Eubacteria

  2. Thermophilic bacteria

  3. Cyanobacteria

  4. None of them
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The cyanobacteria or the blue-green bacteria represent a group of photosynthetic, mostly photolysis-mediated oxygen-evolving monerans (prokaryotes). These are the only organisms able to perform oxygenic photosynthesis that can also fix nitrogen. So, the correct option is 'Cyanobacteria'.

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

Blue-green algae are commonly found growing in paddy fields as they act as a good   

  1. Biofertilizer

  2. Pest controlling agent

  3. Oxygenating organisms

  4. Pollution abatement agent
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Blue-green Algae (BGA) is a type of biofertilizer used as an alga form. Important species are Cyanobacteria, Anabaena, Nostoc, Tolypothrix. The algal mat in paddy fields protects loss of moisture from the soil.
A. Bio-fertilizers are eco-friendly are environmentally safe and have low cost. They are widely used in paddy production. The most common bio-fertilizers are Azospirillum, Phosphobacteria, Blue-green algae, Azolla and mycorrhiza.
So the correct answer is "Biofertilizers".
Multiple choice zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

Which statements are true about heterocyst?
(a) Thick cell wall is permeable to oxygen
(b) It lacks PS-II
(c) PS-I remains active which generates ATP required to fix nitrogen.

  1. All except (a)

  2. All except (b)

  3. All except (c)

  4. All (a), (b) and (c)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
1) heterocyst cells with thick cell films to prohibit oxygen. 
2) heterocysts do not have a utilitarian photosystem II. 
3) The settled carbon and nitrogen sources are traded through diverts between the cells in the fiber. Heterocysts keep up photosystem I, enabling them to create ATP by cyclic photophosphorylation as there is no release of $O _2$
So, the correct answer is 'All except (a)'
Multiple choice zoology microbes in human welfare biofertilizers microbes as biocontrol agents and biofertilizers manuring

Cyanobacteria came into existence ....... years ago.

  1. 2.9 billion

  2. 3.4 billion

  3. 1 million

  4. 44 thousands
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stromatolites are layered bio-chemical structures formed in shallow water by the trapping, binding and cementation of sediments by microorganisms, especially cyanobacteria. Stromatolites provide ancient records of life on earth by fossil remains, which might date from more than 3.5 billion years ago.

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

How many of the following organisms can be used as biofertilizers?
Azolla, Thiobacillus, Frankia, Glomus, Pseudomonas, Anthoceros, Klebsiella.

  1. $3$
  2. $5$
  3. $2$
  4. $1$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Among the list, Azolla, Frankia, and Glomus are commonly used as biofertilizers. Thiobacillus, Pseudomonas, Anthoceros, and Klebsiella are generally not classified as standard agricultural biofertilizers in this context.