Tag: classification of microbes

Questions Related to classification of microbes

Cyanobacteria (Nostoc) is

  1. Oxygenic with nitrogenase

  2. Oxygenic without nitrogenase

  3. Non-oxygenic with nitrigenase

  4. Non-oxygenic without nitrogenase


Correct Option: A
Explanation:
Nostoc is a genus of Cyanobacteria. It is oxygenic photosynthetic bacteria. It has ability to synthesize their own food in presence of oxygen. 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 'Oxygenic with nitrogenase.'

Bacteria found in hot acidic aerobic conditions are

  1. Halophiles

  2. Thermoacidophiles

  3. Methanogens

  4. Rickettsiae


Correct Option: B
Explanation:

Halophiles are bacteria that are found in high salt concentration conditions. Examples include Halobacillus, Halococcus. Bacteria found in hot acidic aerobic conditions are called as thermoacidophiles. Examples include Thermoplasma, Thermococci. Methanogens are organisms that produces methane gas. Example includes Methanococcus. Rickettsiae are obligate intracellular, Gram-negative bacteria found in ticks, lice, fleas, mites, mammals. Example includes Rickettsia rickettsii.

Thus, the correct answer is 'Thermoacidophiles.'

Bacteria involved in production of methane gas are

  1. Actinomycetes

  2. Methanogens

  3. Methanotrophs

  4. Cyanobacteria


Correct Option: B
Explanation:

Methanogens belongs to Archeabacteria groups. They are involved in the production of methane gas or marshy gas. They are capable of producing methange gas in marshy areas. Examples include Methanococcus, Methanobacterium.

Thus, the correct answer is 'Methanogens.'

Which statement is true about domain archaea?

  1. They differ from both prokaryotes and eukaryotes

  2. They completely differ from prokaryotes

  3. They resemble eukarya in all aspects

  4. They have some novel features absent in other prokaryotes and eukaryotes


Correct Option: D
Explanation:

Domains Archaea contains single-celled microorganisms. These are prokaryotes. They do not have a true nucleus or membrane-bound organelles. They lack peptidoglycan in the cell wall. However, they have some novel features absent in other prokaryotes and eukaryotes. Instead of ester bonds like in prokaryotes and eukaryotes, they have ether bonds connecting fatty acids to molecules of glycerol. 

Thus, the correct answer is 'They have some novel features absent in other prokaryotes and eukaryotes.'

Thermococcus, Methanococcus and Methanobacterium exemplify

  1. Bacteria whose DNA is relaxed or positively supercoiled but which has a cytoskeleton as well as mitochondria

  2. Bacteria that contain a cytoskeleton and ribosome

  3. Archaebacteria that contain proteins homologous to eukaryotic core histones

  4. Archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled


Correct Option: C

Archaea differ from eubacteria in one of the following features

  1. They have a rigid wall

  2. Their cell wall lacks peptidoglycan component

  3. They have $16$ sRNA

  4. They are very ancient


Correct Option: B

Organisms called methanogens are most abundant in

  1. Polluted stream

  2. Cattle yard

  3. Sulphur rock

  4. Hot spring


Correct Option: B
Explanation:

Methanogen belongs to Archaebacteria group. They are capable of producing methane gas or marshy gas or biogas. They produces methane gas in marshy areas. They are most abundant in marshy areas and cattle yard where cow sheds are present. The methange gas produces a peculiar odour in these areas.

Thus, the correct answer is 'Cattle yard.'

Archaebacteria live in harsh habitat like

  1. Extreme salty area

  2. Hot springs

  3. Marshy areas

  4. All of the above


Correct Option: D
Explanation:

Archaebacteria are prokaryotes without true nucleus. They are of mainly 3 types, halophiles, thermophiles and methanogesn. They live in harsh habitat. Halophiles archaebacteria are found in extreme salty areas. Thermophiles are found in hot springs where temperature is extremely high. Methanogens are found in marshy areas and produce methange gas.

Thus, the correct answer is 'All of the above.'

Some hyperthermophilic organisms that grow in highly acidic $(pH _2)$ habitats belong to two groups

  1. Cyanobacteria and diatoms

  2. Protists and mosses

  3. Liverworts and yeasts

  4. Eubacteria and archaea


Correct Option: D
Explanation:
  • Many thermophiles are archaea, while thermophilic eubacteria are suggested to have been among the earliest bacteria.
  •  Many of these require elemental sulfur for growth. Some are anaerobes, that use the sulfur as an electron acceptor during cellular respiration. 
  • Some are lithotrophs, that oxidize sulfur to sulfuric acid, thus requiring the microorganism to be adapted to very low pH as well. These organisms are inhabitants of hot, sulfur-rich environments such as hot springs and geysers etc. Option D is correct.

A peculiar odour found in marshy areas and cow sheds is of gas produced by

  1. Archaebacteria

  2. Cyanobacteria

  3. Slime Moulds

  4. Mycoplasma


Correct Option: A
Explanation:

Methanogen belongs to Archaebacteria group. They are capable of producing methane gas or marshy gas or biogas. They produces methane gas in marshy areas and cow sheds. This produces a peculiar odour.

Thus, the correct answer is 'Archaebacteria.'