Biological Classification MCQs: Recommended MCQs

Biological classification is a way of organizing living organisms into categories based on their characteristics. It helps us to better understand the diversity of life on Earth and forms the base for simplifying biology. The classification system helps us to identify, describe and categorize organisms. It is based on the assumption that all living things are related and can be arranged in an order with shared characteristics.

Also Read

• The Living World

• Binomial Nomenclature

• What is Taxonomy

• Biological Classification

Biological Classification MCQs

1. Which organism can be found in an extremely salty environment?

a. Eubacteria

b. Archaebacteria

c. Cyanobacteria

d. Mycobacteria

Ans. b. Archaebacteria

Explanation: Archaebacteria can be found in extremely salty environments such as salt lakes or brines. They are well adapted to living in these harsh conditions and can survive in high salinity due to their unique cell membrane structures.

2. What classification domain did Linnaeus use?

a. Artificial system

b. Natural system

c. Phylogenetic system

d. Asexual system

Ans. a. Artificial system

Explanation: Linnaeus used the artificial system of classification, which was based on superficial physical characteristics rather than evolutionary relationships. He organized living organisms into groups based on easily observable traits such as their overall shape, size, and number of legs. This system was later replaced by the natural system, which took into account evolutionary relationships and genetic similarities between species.

3. Minimum taxon classification all

a. Kingdom

b. Family

c. Variety

d. Species

Ans. d. Species

Explanation: The minimum taxon classification level is the species. Species is the most basic unit of classification, and it refers to a group of organisms that share similar physical and genetic characteristics and can interbreed to produce viable offspring. All living organisms are classified by their species, and other higher levels of classification, such as family or kingdom, include multiple species that share certain characteristics.

4. Archaea and nitrogen-fixing organisms belong to which kingdom?

a. Animalia

b. Plantae

c. Monera

d. Fungi

Ans. c. Monera

Explanation: Archaea and nitrogen-fixing organisms belong to the kingdom Monera. This kingdom was traditionally classified as including all prokaryotic organisms, which lack a distinct nucleus and membrane-bound organelles. However, the Monera kingdom has been further divided into two domains: Bacteria and Archaea. Archaea are a group of prokaryotic organisms that are often found in extreme environments, such as high temperatures or high salinity. Nitrogen-fixing organisms are a type of bacteria that can convert atmospheric nitrogen into a form that plants can use.

5. What classification system did Bentham and Hooker propose?

a. Numerical

b. Phylogenetic

c. Artificial

d. Natural

Ans. d. Natural

Explanation: Bentham and Hooker proposed the natural classification system, which organizes living organisms based on their evolutionary relationships and genetic similarities. This classification system groups organisms based on their shared ancestry and evolutionary history, rather than superficial physical characteristics. The natural classification system aims to reflect the true evolutionary relationships between organisms, rather than simply grouping them based on similarities that may be the result of convergent evolution. This system is widely used in modern taxonomy and has been refined with advances in molecular biology and genetics.

6. What is the basis of classification in the system of King Oh?

a. Structure of the nucleus

b. Structure of cell wall

c. Asexual Reproduction

d. Mode of Nutrition

Ans. d. Mode of Nutrition

Explanation: The basis of classification in the system of King oh is the mode of nutrition. King Oh proposed a classification system that categorises organisms based on how they obtain their nutrients. The three main categories in this system are autotrophs, heterotrophs, and saprotrophs. Autotrophs are organisms that can produce their food using energy from sunlight or other sources, while heterotrophs must consume other organisms to obtain nutrients. Saprotrophs obtain nutrients by breaking down dead organic matter.

7. Which of the following is the highest category of biological classification?

a. Phylum

b. Kingdom

c. Species

d. Genus

Ans. b. Kingdom

Explanation: The highest category of biological classification is the Kingdom. This is the broadest level of classification and groups organisms based on fundamental characteristics such as cell structure, mode of nutrition, and reproduction.

There are currently six recognized kingdoms: Animalia, Plantae, Fungi, Protista, Archaea, and Bacteria. Each of these kingdoms includes multiple lower levels of classification, such as phylum, class, order, family, genus, and species.

8. Causes of African sleeping sickness include

a. Trypanozoma cruzi

b. T. Tangela

c. T. rhodesiense

d. T. gambiense

Ans. d. T. gambiense

Explanation: African sleeping sickness is caused by Trypanosoma gambiense. This is a parasitic protozoan that is transmitted to humans by the tsetse fly. It can cause fever, fatigue, headaches, and other symptoms and can be fatal if left untreated. There is another form of the disease, caused by Trypanosoma rhodesiense, which is generally more acute and has a more rapid onset of symptoms.

9. Linnaeus developed a system of nomenclature known as

a. Vernacular

b. Monomial

c. Polynomial

d. Binomial

Ans. d. Binomial

Explanation: Linnaeus developed a system of nomenclature known as binomial nomenclature. This system involves giving each species a two-part scientific name consisting of a genus name and a species name. For example, the scientific name for humans is Homo sapiens, with Homo being the genus name and sapiens being the species name. This system allows for clear and precise communication about different species, and it is still widely used today in the field of taxonomy.

10. What is a taxon?

a. A group of related families

b. A type of living organism

c. A group of related species

d. A group of any ranking

Ans. d. A group of any ranking

Explanation: A taxon is a group of any ranking used in biological classification. This can refer to a group of related families, genera, species, or any other level of classification. Taxa are used to organise living organisms into groups based on their evolutionary relationships and physical characteristics. Different levels of taxa can be combined to form higher-level groupings, such as orders, classes, and phyla. Taxa provide a standardised system for categorising and naming living organisms, making it easier for scientists to communicate and study biodiversity.

11. A classification of two kingdoms is given

1. c.linnaeus

2. john ray

3. Huxley

4. Whittaker

Ans. c. Huxley

Explanation: The classification of two kingdoms refers to the system of classification proposed by biologists to classify living organisms into two kingdoms: Plantae and Animalia. The individuals mentioned in the question are biologists who have contributed to the development of the classification system. Among the given options, "c. Huxley" is the correct answer as he proposed the two-kingdom system of classification in 1866.

12. Choose the right pair.

1. Parasitic fungi – feeds on plants and animals

2. Saprotrophic fungi – feeds on dead and decaying organic matter

3. Symbiotic fungi – mycorrhiza

4. All of the above are true

Ans. d.All of the above are true

Explanation: The statement "All of the above are true" is the correct answer.

Parasitic fungi are known to feed on plants and animals, Saprotrophic fungi obtain nutrients by decomposing dead and decaying organic matter, and Symbiotic fungi form associations with the roots of plants to form mycorrhizae.

13. Which of the following is used in biochemical and genetic research?

1. Claviceps

2. Aspergillus

3. Neurospora

4. Mucor

Ans. c. Neurospora

Explanation: The correct answer is "c. Neurospora." Neurospora is a genus of fungi that has been widely used in biochemical and genetic research as a model organism. It has a short life cycle and well-understood genetics, making it a useful tool for genetic and biochemical experiments.

14. Select the correct match.

1. Photosynthetic autotrophs – Nutrient recycling

2. Chemosynthetic autotrophs – Nitrogen fixation

3. Heterotrophic bacteria – Production of antibiotics

4. Mycoplasma – Production of curd

Ans. c. Heterotrophic bacteria – Production of antibiotics

Explanation: The correct answer is "c. Heterotrophic bacteria – Production of antibiotics." Heterotrophic bacteria are bacteria that require an external source of organic compounds to grow and reproduce. Many species of heterotrophic bacteria are known to produce antibiotics that are used in medicine to treat bacterial infections. Photosynthetic autotrophs are not involved in nutrient recycling, but they produce organic compounds through photosynthesis.

15. Given the binomial nomenclature

1. Huxley

2. ray

3. darwin

4. Linnaeus

Ans. d. Linnaeus

Explanation: The correct answer is "d. Linnaeus." Binomial nomenclature is a system of naming living organisms by giving them a two-part Latin name consisting of a genus name and a species name. It was developed by Carl Linnaeus in the 18th century and is still widely used today.

16. Which of the following is an indicator of air pollution?

1. Mycorrhiza

2. Agaricus

3. Lichens

4. Common mushrooms

Ans. c.Lichens

Explanation: The correct answer is "c. Lichens." Lichens are composite organisms made up of a fungus and a photosynthetic partner (either algae or cyanobacteria) that grow together in a symbiotic relationship. Lichens are sensitive to air pollution and can be used as bioindicators of air quality. They are often used to monitor levels of sulfur dioxide and other pollutants in the atmosphere.

17. The natural classification system is based on

1. morphology

2. evolutionary trend

3. anatomy

4. all of the above

Ans. d. all of the above

Explanation: The correct answer is "d. all of the above." The natural classification system is a system of organizing living organisms into groups based on their evolutionary relationships. It takes into account various aspects of the organisms such as their morphology, anatomy, and evolutionary trends to classify them into different groups.

18. Potato spindle tuber disease can be caused by

1. Phycobiont

2. Virus

3. Bacteria

4. Viroids

Ans. d. Viroids

Explanation: The correct answer is "d. Viroids." Potato spindle tuber disease is a plant disease caused by viroids, which are small, circular RNA molecules that can cause disease in plants. Viroids are similar to viruses but do not have a protein coat and are smaller in size. They cause diseases in plants by interfering with the normal functioning of the plant's cells.

19. Quinine is

1. Puccinia

2. Neurospora

3. Gonyaulax

4. Cinchona

Ans. a.Puccinia

Explanation: The correct answer is "d. Cinchona." Quinine is an alkaloid that is extracted from the bark of the Cinchona tree. It is used as a medication to treat malaria and has been used for centuries by indigenous peoples in South America for its medicinal properties.

20. According to Wang Wu's classification, which of the following does not contain a nuclear envelope?

1. Protista

2. Monera

3. Fungi

4. Animalia

Ans. (b) Monera

Explanation: Wang Wu's classification system is an old and outdated system of classification that was proposed in the early 20th century. According to this system, there are four kingdoms of life: Protista, Monera, Fungi, and Animalia. The correct answer is "b. Monera" because Monera is a kingdom of life that contains prokaryotic organisms such as bacteria and cyanobacteria, which do not have a true nucleus with a nuclear envelope. Protista, Fungi, and Animalia are eukaryotic organisms that have a true nucleus with a nuclear envelope.

21. Which of the following processes is involved in the reproduction of protists?

1. Cell fusion and zygote formation

2. Spore formation and fragmentation

3. Budding and spore formation

4. Binary fission and fragmentation

Ans. a. Cell fusion and zygote formation

Explanation: Cell fusion and zygote formation." Protists are a diverse group of eukaryotic organisms that reproduce through a variety of methods. However, many protists reproduce sexually through the process of cell fusion and zygote formation. This involves the fusion of two haploid cells to form a diploid zygote, which then undergoes meiosis to produce haploid offspring.

22. Prokaryotes have genetic material

1. circular DNA without histones

2. linear DNA without histones

3. circular DNA with histones.

4. linear DNA with histones

Ans. a. circular DNA without histones

Explanation: Prokaryotes are organisms that lack a true nucleus and other membrane-bound organelles. They have a single circular chromosome made of DNA that is not associated with histone proteins. This is in contrast to eukaryotes, which have linear chromosomes that are wrapped around histone proteins.

23. Bacteria are a group of prokaryotic organisms characterised by

1. All of the above

2. Simple structure and complex behaviour

3. 70 S ribosomes

4. Peptidoglycan cell wall

Ans. a. All of the above

Explanation: Bacteria are a diverse group of prokaryotic organisms that are characterised by their simple cellular structure, complex behaviour, 70 S ribosomes, and peptidoglycan cell wall. They are found in almost every environment on Earth and play important roles in many ecological processes such as nutrient cycling and decomposition.

24. Choose the right match

1. Desmids - Chrysophytes

2. Gymnodinium - Hemicellulosic plates in wall

3. Euglena Chlorophyll a & c

4. Gonyaulax - Red sea

Ans. a. Desmids - Chrysophytes

Explanation: Desmids are a group of green algae that are classified as members of the phylum Chlorophyta. They are characterized by their symmetrical cell shape and intricate cell walls. Chrysophytes are a group of protists that are characterized by the presence of golden-coloured chloroplasts. Gymnodinium is a genus of dinoflagellates that have hemicellulosic plates in their cell walls. Euglena is a genus of protists that have chlorophyll a and b in their chloroplasts. Gonyaulax is a genus of dinoflagellates that are known for causing red tides in the ocean.

25. Nuclear dysplasia is seen

1. Paramecium

2. Plasmodium

3. Amoeba

4. Trypanosoma

Ans. a. Paramecium

Explanation: Paramecium. Nuclear dysplasia refers to the abnormal development of the nucleus, which is a characteristic feature of Paramecium. Paramecium is a unicellular, ciliated protozoan that belongs to the phylum Ciliophora. It has a distinct nuclear structure, with two nuclei: the macronucleus and micronucleus. Nuclear dysplasia can occur due to various reasons such as genetic mutations, environmental factors, and infections.

26. The most common types of genetic material present in bacteriophages are

1. ds DNA

2. ds RNA

3. ss RNA

4. ss DNA

Answer: a. ds DNA

Explanation: Bacteriophages are viruses that infect bacteria. They contain genetic material in the form of either DNA or RNA. However, the most common type of genetic material found in bacteriophages is double-stranded DNA (ds DNA). Some bacteriophages may also have single-stranded DNA (ss DNA) or RNA (ss RNA) as their genetic material. The ds DNA in bacteriophages can be linear or circular and can range in size from a few kilobases to over 200 kilobases. The genetic material of bacteriophages encodes for various proteins that are necessary for their replication and survival.

27. Which of the following is the correct taxonomic hierarchy?

a. Kingdom, Species, Genus, Family, Order, Class

b. Kingdom, Family, Genus, Species, Order, Class

c. Kingdom, Order, Family, Genus, Species, Class

d. Kingdom, Class, Order, Family, Genus, Species

Answer: d. Kingdom, Class, Order, Family, Genus, Species

Explanation: The correct answer is d. Kingdom, Class, Order, Family, Genus, Species. This is the standard taxonomic hierarchy used in biology to classify and organize living organisms based on their characteristics and evolutionary relationships. Kingdom is the highest level of classification, followed by Phylum, Class, Order, Family, Genus, and Species.

28. Eubacteria can be distinguished from archaea by

1. Cell wall

2. Ribosomes

3. Gene of tRNA

4. Nutrition

Answer: a. Cell wall

Explanation: Eubacteria can be distinguished from archaea by

The correct answer is a. Cell wall. Eubacteria and archaea are both prokaryotic microorganisms, but they have distinct differences in their cell wall structure. Eubacteria have a peptidoglycan cell wall, which is absent in archaea. Instead, archaea have a cell wall made up of unique molecules such as pseudomurein, which is not found in eubacteria. Other differences between eubacteria and archaea include differences in ribosomes, tRNA genes, and metabolism.

29. The main basis for classification in the five international

1. mode of nutrition

2. asexual reproduction

3. structure of nucleus

4. structure of cell wall

Answer: a. mode of nutrition

Explanation: The five international systems of classification are based on different criteria such as mode of nutrition, body plan, and evolutionary relationships. The most commonly used system of classification is the Linnaean system, which is based on the morphology and anatomy of organisms. The five-kingdom system of classification, proposed by Whittaker in 1969, is based on the mode of nutrition and includes Monera (prokaryotes), Protista (unicellular eukaryotes), Fungi (multicellular eukaryotes that absorb nutrients), Plantae (multicellular eukaryotes that photosynthesize), and Animalia (multicellular eukaryotes that ingest food).

30. The phenetic classification is based on

1. Observable characteristics of existing organisms

2. Dendrograms based on DNA characteristics

3. The ancestral lineage of existing organisms

4. Sexual characteristics

Ans. Observable characteristics of existing organisms

Explanation: Phenetic classification involves the use of various mathematical algorithms to generate numerical values that represent the degree of similarity between different organisms, which are then used to construct dendrograms or cluster diagrams that show the relationships between them.

Phenetic classification can be useful in identifying and classifying organisms that have similar phenotypes, but it has limitations in distinguishing between organisms that may have evolved similar traits independently.

31. In Ojukwu, Chlorella and Chlamydomonas fall under the following.

1. Algae

2. Plantae

3. Monera

4. Protista

Ans. d Protista

Explanation: The correct answer is d. Protista. Ojukwu is a taxonomic system that classifies organisms into five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia. Chlorella and Chlamydomonas are unicellular green algae that belong to the kingdom Protista. These organisms have complex cell structures and carry out photosynthesis, but they lack the specialised tissues and organs found in higher plants.

32. What are classifications based on genetic and evolutionary relationships?

1. Phonetics

2. Biosystematic

3. Numerical taxonomy

4. Cladistics

Ans. d. Cladistics

Explanation: The correct answer is d. Cladistics. Cladistics is a method of classification that groups organisms based on their evolutionary relationships, using molecular and genetic data to determine the branching patterns of evolutionary lineages. Cladistics seeks to identify groups of organisms that share a common ancestor and have unique features that distinguish them from other groups. This approach relies on the principle of parsimony, which assumes that the simplest explanation for observed similarities and differences among organisms is the most likely explanation.

33. Which group has the highest nutrient diversity?

1. Monera

2. Plantae

3. Fungi

4. Animalia

Ans- a. Monera

Explanation: The correct answer is a. Monera. Monera, which includes bacteria and archaea, have the highest nutrient diversity among the five kingdoms of living organisms. Bacteria and archaea can be found in a wide range of environments, from soil and water to extreme habitats like hot springs and deep-sea hydrothermal vents. They can also utilise a wide variety of nutrients and metabolic pathways, including photosynthesis, chemosynthesis, fermentation, and respiration.

34. Another name for cyanobacteria

1. Blue-green algae

2. Golden algae

3. Protists

4. Slime moulds

Ans- a. Blue-green algae

Explanation: The correct answer is a. Blue-green algae. Cyanobacteria are photosynthetic bacteria that are also known as blue-green algae. They are characterised by their ability to perform oxygenic photosynthesis, which involves the conversion of light energy into chemical energy to produce carbohydrates and release oxygen as a byproduct. Cyanobacteria are important primary producers in aquatic environments and play a critical role in global carbon and nitrogen cycles

35. General characteristics of archaea cell

1. Structure of cell membrane

2. Structure of cell wall

3. Has fatty acid synthetase

4. Structure of flagellin protein

Ans- c. Has fatty acid synthetase

Explanation: The correct answer is c. Has fatty acid synthetase. Archaea are a group of prokaryotic organisms that are distinct from bacteria and eukaryotes. They are characterized by many unique features, including the presence of ether-linked phospholipids in their cell membranes and the absence of peptidoglycan in their cell walls.

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