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MCQs on Archaebacteria

MCQs on Archaebacteria: Find the multiple choice questions on Archaebacteria, frequently asked for all competitive examinations.

After the evolution of life, archaebacteria are the earliest form of living thing found on the planet. Archaebacteria are a unique type of bacteria that can be found in a variety of difficult environments, including hot springs, excessively saline places, and marshy areas. Furthermore, Archaebacteria are frequently classified as bacteria since many of their characteristics are similar to those of bacteria when viewed under a microscope. Monera is the kingdom that includes Archaebacteria.

Archaebacteria are a unique type of bacteria that can thrive in the hardest environments. Archaebacteria is a type of ancient living organism found on the planet. The cell wall structure of archaebacteria differs from that of other bacteria. This property allows archaebacteria to thrive in harsh environments.


Q.1. Which of the microorganisms thrive under extreme environmental conditions like high temperature and acidic pH, lack of oxygen, and high salt concentration?

    1. Cyanobacteria
    2. Archaebacteria
    3. Eubacteria
    4. All of the Above

Answer: The Correct answer is Archaebacteria. Archaebacteria are the world’s earliest living organisms. They are unicellular prokaryotes belonging to the Archaea kingdom. They were found in 1977 and were categorized as bacteria at the time. When examined under a microscope, most archaebacterial resemble bacteria. They are, however, not the same as bacteria or eukaryotic organisms. Archaebacteria can be found in extreme environments such as volcanic vents or the ocean’s depths. They can easily survive in severe environments such as sulfide-rich gas vents at sea, hot springs, and boiling mud around volcanoes.

Q.2.Which one is true with respect to Archaebacteria?

    1. Archaebacteria are fossils
    2. Archaebacteria are halophiles
    3. Archaebacteria are old living entities
    4. Archaebacteria are photosynthetic

Answer: The Correct answer is Archaebacteria are old living entities. Archaebacteria may thrive in harsh environmental conditions that are thought to have occurred on the early Earth. These are said to depict the first forms of life. As a result, archaebacteria are known as the “oldest, living beings”.

Q.3. The two categories of hyperthermophilic organisms that live in strongly acidic (pH2) environments are known as

    1. Cyanobacteria and Diatoms
    2. Protists and Mosses
    3. Eubacteria and Archaea
    4. Liverworts and Yeasts

Answer: The Correct Answer is Eubacteria and Archaea. Monerans are divided into two groups: archaebacteria (old bacteria) and eubacteria (modern bacteria) (true bacteria). There are two types of Eubacteria: bacteria and cyanobacteria. Thermoacidophiles are a type of archaebacteria that thrive in an acidic (pH 2) environment with high temperatures (up to 110°C).

Q.4.In Extreme Saline Conditions which of the Following is found?

    1. Mycobacteria
    2. Eubacteria
    3. Cyanobacteria
    4. Archaebacteria

Answer: The Correct answer is Archaebacteria. Archaebacteria can be found in adverse circumstances. In highly saline environments, halophiles can be discovered.

Q.5.Prokaryotes classified as ______ are the most abundant and helpful to humans in the creation of curd from milk and antibiotics.

    1. Cyanobacteria
    2. Archaebacteria
    3. Chemosynthetic autotrophs
    4. Heterotrophic bacteria

Answer: The Correct Answer is Heterotrophic bacteria. For growth, heterotrophic bacteria require an organic carbon source (i.e., they derive energy and carbon from organic compounds). The following are some of the most important commercial applications of heterotrophic bacteria:

They improve the soil’s fertility by fixing nitrogen.

Milk, cheese, butter and wine are used to make curd and yoghurt.

Antibiotics are manufactured.

They are an important component in biogeochemical cycles, in which they recycle vital components like nitrogen and carbon.

Oil spills must be cleaned up.

Q.6. Methanogens Belong to ……….

    1. Dinoflagellates
    2. Eubacteria
    3. Archaebacteria
    4. Slime moulds

Answer: The Correct Answer is Archaebacteria. Carl Woese proposed dividing life into three kingdoms, Archaebacteria, Eubacteria, and Eukaryota, which became known as domains. The archaebacteria are a group of primordial prokaryotic organisms that includes methanogens. These prokaryotes are unicellular, anaerobic, and autotrophic.

The lack of peptidoglycan in the cell wall allows it to convert carbon dioxide and hydrogen into methane gas. The hydrogen acts as an electron donor in the carbon dioxide reduction process.

Q.7. Archaebacteria and eubacteria vary in which of the following characteristics?

    1. Mode of nutrition
    2. Cell shape
    3. Cell membrane structure
    4. Mode of reproduction

Answer: The Correct Option is Cell Membrane Structure. Archaebacteria vary from eubacteria in that their cell membrane is made up mostly of glycerol-ester lipids, whereas archaebacteria’s is made up of glycerol-ether lipid. Chemically, ether lipids are more resistant than ester lipids.

Q.8. Methanococcus, Thermococcus, and Methanobacterium are examples of 

    1. Bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria
    2. Bacteria that contain a cytoskeleton and ribosomes
    3. Archaebacteria that contain protein homologous to eukaryotic core histones
    4. Archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled.

Answer: The Correct Answer is Archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled. Thermococcus, Methanococcus, and Methanobacterium are archaea with shorter histones that are organised in tetramers than eukaryotic histones.

Q.9. Which of the following statements concerning archaea is true after the new classification of living beings into three domains of life (bacteria, archaea, and eukarya)?

    1. Completely differ from prokaryotes
    2. Resembles eukarya in all respects
    3. Have some novel features that are absent in other eukaryotes and prokaryotes
    4. Completely differ from both eukaryotes and prokaryotes

Answer: The Correct Answer is Have some novel features that are absent in other eukaryotes and prokaryotes. Plants and animals are classified as members of the same kingdom as archaebacteria. Archaebacteria are organisms that possess unique characteristics not found in bacteria or eukaryotes. 

Methanogens are organisms that can create methane gas. These creatures’ DNA is usually found in a relaxed or positively coiled state. These creatures’ cell walls are devoid of lipids, peptidoglycan, and other proteins.

Q.10. Which of the following elements are most likely to be found in deep seawater?

    1. Archaebacteria
    2. Eubacteria
    3. Saprophytic fungi
    4. Blue-green algae

Answer: The Correct Answer is Archaebacteria. Because of their ability to thrive in harsh environments, archaebacteria are also known as extremophiles. Increased pressure, reduced visibility, and a lack of nutrition are all characteristics of the deep marine habitat. Bacteria can also be found in the benthic zone.