The Three-domain System
Questions and Answers
- 1.
Who developed the three-domain system?
Explanation
Carl Woese developed the three-domain system. This system categorizes all living organisms into three domains: Archaea, Bacteria, and Eukarya. Woese's research in the 1970s revolutionized our understanding of evolutionary relationships among organisms by using molecular sequencing techniques to study the genetic differences between organisms. He proposed the three-domain system based on the differences in the genetic sequences of the small subunit ribosomal RNA. This system has since become widely accepted and has had a significant impact on the field of biology.Rate this question:
- 2.
In what year was the three-domain system developed?
- 3.
How many kingdoms does the three-domain system have?
Explanation
The three-domain system categorizes all living organisms into three domains: Archaea, Bacteria, and Eukarya. Each domain represents a distinct group of organisms with unique characteristics. Therefore, the three-domain system has six kingdoms in total, with two kingdoms in each domain.Rate this question:
- 4.
What are the three domains in the three-domain system?
- A.
Archaebacteria
- B.
Archae
- C.
Bacteria
- D.
Eukaryote
- E.
Prokaryote
- F.
Eukarya
Correct Answer(s)
B. Archae
C. Bacteria
F. EukaryaExplanation
The three domains in the three-domain system are Archae, Bacteria, and Eukarya. This system categorizes all living organisms into one of these three domains based on their cellular structure and genetic makeup. Archae consists of organisms that are often found in extreme environments and have unique biochemical properties. Bacteria includes all prokaryotic organisms, which lack a nucleus and membrane-bound organelles. Eukarya comprises all eukaryotic organisms, which have a true nucleus and membrane-bound organelles. This system provides a more accurate and comprehensive classification of organisms compared to the traditional five-kingdom system.Rate this question:
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- 5.
Which domains are prokaryotic?
Correct Answer(s)
Archaea, Bacteria, Bacteria, ArchaeaExplanation
Bacteria: These single-celled organisms are found in a wide range of environments, from soil and water to inside the bodies of other organisms. They have a simple cell structure without a nucleus.
Archaea: Archaea are single-celled microorganisms that can survive in extreme environments such as hot springs, salt flats, and deep-sea hydrothermal vents. They also lack a nucleus and are structurally similar to bacteria but differ in various biochemical aspects.Rate this question:
- 6.
Which domains are eukaryotic?
Correct Answer(s)
EukaryaExplanation
Eukarya is the correct answer because it is the domain that includes all eukaryotic organisms. Eukaryotes are characterized by having cells with a nucleus and membrane-bound organelles. This domain includes organisms such as animals, plants, fungi, and protists.Rate this question:
- 7.
Which kingdom(s) does the Archaea domain consist of?
Correct Answer(s)
ArchaebacteriaExplanation
The Archaea domain consists of the kingdom Archaebacteria. Archaea are a group of single-celled microorganisms that are similar to bacteria in size and shape but are biochemically and genetically different. They are known for their ability to survive in extreme environments such as hot springs, deep-sea hydrothermal vents, and acidic environments. The kingdom Archaebacteria includes various types of Archaea, such as methanogens, halophiles, and thermophiles. These organisms play important roles in various ecosystems and have unique metabolic processes that make them distinct from other organisms.Rate this question:
- 8.
Which kingdom(s) does the Bacteria domain consist of?
Correct Answer(s)
EubacteriaExplanation
The Bacteria domain consists of the Eubacteria kingdom. This kingdom includes a wide range of bacteria that are found in various environments such as soil, water, and the human body. Eubacteria are prokaryotic organisms, meaning they lack a nucleus and other membrane-bound organelles. They can be either beneficial or harmful to humans, with some species causing diseases while others play important roles in nutrient cycling and digestion. Overall, the Eubacteria kingdom is diverse and plays a significant role in various ecosystems.Rate this question:
- 9.
Which kingdom(s) does the Eukarya domain consist of?
- A.
Eubacteria
- B.
Animalia
- C.
Protista
- D.
Archaebacteria
- E.
Fungi
- F.
Plantae
Correct Answer(s)
B. Animalia
C. Protista
E. Fungi
F. PlantaeExplanation
The Eukarya domain consists of four kingdoms: Animalia, Protista, Fungi, and Plantae. These kingdoms are characterized by having eukaryotic cells, which means their cells have a nucleus and other membrane-bound organelles. Animalia includes multicellular animals, Protista includes unicellular organisms like protozoa and algae, Fungi includes organisms like mushrooms and yeasts, and Plantae includes multicellular plants. These kingdoms are part of the Eukarya domain because they share similar characteristics and evolutionary history.Rate this question:
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- 10.
Which domain is characterized by organisms that live in extreme environments?
Correct Answer(s)
ArchaeaExplanation
Archaea is the correct answer because it is a domain of single-celled microorganisms that are known for living in extreme environments such as hot springs, deep-sea hydrothermal vents, and acidic or alkaline environments. These organisms are able to survive in these harsh conditions due to their unique biochemistry and adaptations, making them well-suited for extreme environments.Rate this question:
- 11.
Which domain is characterised by multi-cellular organisms?
Correct Answer(s)
EukaryaExplanation
Eukarya is the correct answer because it is the domain that includes all multi-cellular organisms. Eukarya is one of the three domains of life, along with Bacteria and Archaea. Organisms in the domain Eukarya have cells that contain a nucleus and other membrane-bound organelles. This domain includes plants, animals, fungi, and protists, all of which are multi-cellular organisms.Rate this question:
- 12.
Which domain is characterised by the most prolific reproducers?
Correct Answer(s)
BacteriaExplanation
Bacteria are known for their ability to reproduce rapidly and efficiently, making them the most prolific reproducers among all domains. They have a short generation time and can reproduce through various methods such as binary fission, conjugation, and transformation. This high reproductive capacity allows bacteria to quickly populate and adapt to different environments, making them one of the most successful and abundant organisms on Earth.Rate this question:
- 13.
Humans belong to which domain?
- A.
Bacteria
- B.
Eubacteria
- C.
Archaea
- D.
Eukarya
Correct Answer
D. EukaryaExplanation
Humans belong to the domain Eukarya. This domain includes all organisms that have cells with a nucleus and membrane-bound organelles, such as plants, animals, fungi, and protists. Humans are multicellular organisms with complex structures and functions, which is characteristic of organisms in the domain Eukarya.Rate this question:
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- 14.
Humans belong to which kingdom?
- A.
Eukarya
- B.
Animalia
- C.
Protista
- D.
Archaebacteria
Correct Answer
B. AnimaliaExplanation
Humans belong to the kingdom Animalia because they are multicellular organisms that have specialized cells and tissues. They are heterotrophic, meaning they obtain their energy by consuming other organisms. Humans also have a complex body structure, including a well-developed nervous system, which is a characteristic of animals.Rate this question:
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- 15.
Halophiles, organisms that thrive in salt, belong to the Bacteria domain.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Halophiles, organisms that thrive in salt, do not belong to the Bacteria domain. They actually belong to the Archaea domain. Archaea are a distinct group of single-celled microorganisms that have unique cell structures and biochemistry, and they are known to thrive in extreme environments such as high salt concentrations. Bacteria, on the other hand, are a separate domain of microorganisms that can be found in a wide range of environments, including those with low or no salt content. Therefore, the correct answer is False.Rate this question:
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- 16.
Thermoacidophiles, organisms that thrive in acid and high temperatures, belong to the Archaea domain.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Thermoacidophiles are organisms that are able to survive and thrive in environments that are both highly acidic and have high temperatures. These extreme conditions are typically found in volcanic areas and hot springs. Thermoacidophiles are known to belong to the Archaea domain, which is one of the three domains of life, along with Bacteria and Eukarya. Archaea are single-celled microorganisms that have unique characteristics and can survive in extreme environments. Therefore, the statement that thermoacidophiles belong to the Archaea domain is true.Rate this question:
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- 17.
Anthropoda, invertebrate organisms such as insects and arachnids, belong to the Eukarya domain.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Anthropoda, which includes insects and arachnids, are classified as invertebrate organisms. Invertebrates lack a backbone and are part of the animal kingdom. The Eukarya domain consists of organisms with eukaryotic cells, which have a nucleus enclosed within a membrane. Insects and arachnids have eukaryotic cells, so they belong to the Eukarya domain. Therefore, the statement is true.Rate this question:
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- 18.
Syphilis and Lyme disease both belong to the Protista kingdom.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Syphilis and Lyme disease do not belong to the Protista kingdom. They are both caused by bacterial infections. Syphilis is caused by the bacterium Treponema pallidum, while Lyme disease is caused by the bacterium Borrelia burgdorferi. Therefore, the statement that they belong to the Protista kingdom is false.Rate this question:
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- 19.
The difference between prokarytic organisms and eukaryotic organisms is the absense of a nuclear membrane and membrane-bound organelles in the former.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because prokaryotic organisms, such as bacteria, do not have a nuclear membrane or membrane-bound organelles like mitochondria or endoplasmic reticulum. In prokaryotes, the genetic material is not enclosed within a nucleus, but instead, it is present in the cytoplasm. Eukaryotic organisms, on the other hand, have a distinct nucleus that houses the genetic material and various membrane-bound organelles that perform specific functions within the cell.Rate this question:
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- 20.
Prokaryotes and eukaryotes each arose from which ancestor with poorly developed genetic machinery?
- A.
Modern cell
- B.
Primitive cell
- C.
Complex organism
- D.
Single-stranded virus
Correct Answer
B. Primitive cellExplanation
Prokaryotes and eukaryotes evolved from a primitive cell, which is considered the last universal common ancestor (LUCA). This ancestor had simple genetic machinery, which later evolved into more complex structures found in modern cells. Prokaryotes (bacteria and archaea) are simpler, lacking a nucleus, while eukaryotes have a defined nucleus and organelles. The genetic material in the primitive cell likely consisted of RNA or early forms of DNA, enabling replication and basic metabolic processes, forming the foundation for cellular life.Rate this question:
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Mar 18, 2025Quiz Edited by
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Jul 18, 2011Quiz Created by
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