Tag: zoology

Questions Related to zoology

The monerans with heterocysts and oxygenic photosynthesis are

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  1. Eubacteria

  2. Thermophilic bacteria

  3. Cyanobacteria

  4. None of them

Show answer
Correct Option: C
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'.

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

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  1. Biofertilizer

  2. Pest controlling agent

  3. Oxygenating organisms

  4. Pollution abatement agent

Show answer
Correct Option: A
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".

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.

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  1. All except (a)

  2. All except (b)

  3. All except (c)

  4. All (a), (b) and (c)

Show answer
Correct Option: A
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)'

The benificial bacterias are known as

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  1. Pathogens

  2. Probiotic

  3. Cyanobacteria

  4. Plasmid

Show answer
Correct Option: B
Explanation:

Probiotics are also called good bacterias. These are beneficial in nature. Eg.,  Lactobacillus is a probiotic found in the human gut. 

So, the correct answer is option B, Probiotic. 

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

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  1. 2.9 billion

  2. 3.4 billion

  3. 1 million

  4. 44 thousands

Show answer
Correct Option: B
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.

Which one of the following is not used as biofertilizer?

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  1. Bacillus thuringiensis

  2. Anabaena

  3. Nostoc

  4. Rhizobium

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Correct Option: A

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

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  1. $3$

  2. $5$

  3. $2$

  4. $1$

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Correct Option: A

In blue green algae, photosynthesis occurs at

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  1. Chromatophore

  2. Chloroplast

  3. Photosynthetic lamellae or thylakoids

  4. Chromoplast

Show answer
Correct Option: C
Explanation:

Since, BGA is a prokaryotic organism, they lack true nucleus and membrane bound organelles which means that chloroplast (double membrane bound chlorophyll containing plastids) is absent in them. Thus, option B is incorrect. Chromatophores are light reflecting, pigment containing cells. The peripheral region of BGA protoplast contains thylakoids and is termed as chromoplast. Thylakoids contain photosynthetic pigments (chrolophyll a, xanthophylls, phycobilin) in their membranes and serve as site for photosynthesis. Thus, option C is correct and D is incorrect.

Which of the following is correct?

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  1. Cyanobacteria makes mycorrhiza which absorbs phosphate from soil

  2. Azotobacter is symbiotic nitrogen fixing bacteria

  3. In paddy field, cyanobacteria is used to decrease soil microbes

  4. Methanobacterium feed cellulose in anaerobic condition

Show answer
Correct Option: D
Explanation:
  • Certain bacteria, which grow anaerobically on cellulosic material, produce a large amount of methane along with $CO _2$ and $H _2$. These bacteria are collectively called methanogens, and one such common bacterium is Methanobacterium. 
  • These bacteria are present in the rumen (a part of the stomach) of cattle. A lot of cellulosic material present in the food of cattle is also present in the rumen. In the rumen, these bacteria help in the breakdown of cellulose and play an important role in the nutrition of cattle. 
  • Hence Methanobacterium feed cellulose in the anaerobic condition is a true statement.
  • So, the correct answer is 'Methanobacterium feed cellulose in anaerobic condition'.

Which of the following is the only group of organisms capable of using inorganic compounds as source of energy?

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  1. Eukaryotes

  2. Prokaryotes

  3. Virus

  4. None of the above

Show answer
Correct Option: B
Explanation:

On the basis of their energy source, organisms are classified as organotrophic and lithotrophs. Most prokaryotes and all non-phototrophic eukaryotes use organic compounds as their energy source and thus, are referred to as organotrophs. They oxidise organic compounds during cellular respiration and the produced oxygen as a byproduct. But some Cyanobacteria and Archaea use inorganic compounds as an electron donor in electron transport chain and are referred to as lithotrophs, none of the eukaryotes falls in this category. Virus act as non-living outside the cell. It becomes active when it enters the host cell and derives the cellular protein from the host.

Thus, the correct answer is option B.