Free Biodiversity and Variety of Life MCQs with Answers

171. Most of the lichens consist of:

• A. Green algae and ascomycetes.
• B. Brown algae and higher plant.
• C. Green algae and basidiomycetes.
• D. Red algae and ascomycetes.

Explanation: Most lichens consist of A. Green algae and ascomycetes. Let's explain each option and provide more details: Green algae and ascomycetes (A): This is the correct answer. Lichens are typically composed of a mutualistic relationship between a green algal partner and an ascomycete fungal partner. The green algae provide photosynthetic capabilities, while the ascomycete fungi provide a protective structure and absorb water and nutrients from the environment. Brown algae and higher plant (B): Brown algae are not typically involved in lichen associations. Lichens do not contain higher plants but instead consist of a fungal partner and a photosynthetic partner, which is often a green alga. Green algae and basidiomycetes (C): Lichens are not commonly composed of green algae and basidiomycetes. Basidiomycetes are another group of fungi, but lichen associations typically involve ascomycetes, not basidiomycetes. Red algae and ascomycetes (D): Lichens do not typically consist of red algae and ascomycetes. Red algae are not commonly involved in lichen partnerships. Correct Answer: Most lichens consist of "Green algae and ascomycetes" (A). Summary: Lichens are mutualistic associations between a green algal partner (providing photosynthesis) and an ascomycete fungal partner (providing a protective structure and nutrient absorption). This combination allows lichens to thrive in various environments, making them a unique and important ecological component.

172. What is the genetic material in influenza virus?

• A. Double helical DNA.
• B. RNA
• C. Single helix DNA.
• D. None of these

Explanation: The genetic material in the influenza virus is B. RNA.Let's explain each option and provide more details:Double helical DNA (A):Influenza viruses do not have double-stranded DNA as their genetic material. They are classified as RNA viruses.RNA (B):This is the correct answer. Influenza viruses have single-stranded RNA as their genetic material. They belong to the Orthomyxoviridae family of viruses, which are RNA viruses responsible for causing influenza in humans and other animals.Single helix DNA (C):The concept of "single helix DNA" is not applicable in the context of viruses. DNA typically forms a double helix, and influenza viruses do not contain DNA as their genetic material.Correct Answer: The genetic material in the influenza virus is "RNA" (B).Summary:The genetic material in the influenza virus is single-stranded RNA. Influenza viruses are RNA viruses responsible for causing the flu in humans and other animals. This RNA serves as the blueprint for the replication and transcription of viral genes during the infection process.

173. What are the sex organs provided in some bacteria?

• A. Sex pili
• B. Plasmid
• C. Circular DNA
• D. Gametes

Explanation: The term "sex organs" is not applicable to bacteria in the same way it is to sexually reproduce multicellular organisms. However, bacteria do have structures and mechanisms that facilitate genetic exchange. Let's explain each option and provide details: Sex pili (a): This is the correct answer. Bacteria often use sex pili (also known as conjugation pili) to facilitate the transfer of genetic material between cells during a process called conjugation. Sex pili are elongated, filamentous appendages that allow one bacterium to contact and transfer genetic material to another bacterium. Plasmid (b): Plasmids are small, circular DNA molecules that can carry extra genes. While plasmids play a role in the transfer of genetic material during conjugation (a process that involves sex pili), they are not sex organs themselves. Circular DNA (c): Circular DNA is a common form of bacterial genomic DNA. However, it is not a sex organ. Circular DNA refers to the structure of bacterial chromosomes and plasmids, but it does not serve as a sex organ in the traditional sense. Gametes (d): Gametes are reproductive cells involved in sexual reproduction in eukaryotic organisms. Bacteria do not produce gametes, as they primarily reproduce through asexual means like binary fission or through genetic exchange mechanisms such as conjugation. Correct Answer: In some bacteria, the structures involved in the genetic exchange are sex pili (a). Summary: Bacteria do not have sex organs in the way multicellular organisms do. Instead, they use structures like sex pili (conjugation pili) to facilitate genetic exchange during processes like conjugation. Plasmids and circular DNA are related to bacterial genetics but are not sex organs. Bacteria do not produce gametes, as they primarily reproduce asexually or through genetic exchange mechanisms.

174. Which type of DNA is found in bacteria?

• A. Circular free DNA.
• B. Membrane bound DNA.
• C. Straight DNA.
• D. Helical DNA.

Explanation: The type of DNA found in bacteria is a. Circular free DNA. Let's explain each option and provide more details: Circular free DNA (a): This is the correct answer. Bacteria typically have a single circular DNA molecule that is free in the cytoplasm. This circular DNA contains the genetic information necessary for the bacterium's function and replication. Membrane-bound DNA (b): Bacteria do not have membrane-bound DNA. Unlike eukaryotic cells, bacteria lack a true nucleus and do not compartmentalize their DNA within a membrane-bound organelle. Straight DNA (c): The term "straight DNA" is not commonly used in the context of bacterial genetics. Bacterial DNA typically forms a circular structure within the bacterial cell. Helical DNA (d): While the DNA double helix is a common term in genetics, it is not specific to bacteria. The double helical structure of DNA is a fundamental characteristic shared by all organisms with DNA-based genomes. Correct Answer: The type of DNA found in bacteria is "Circular free DNA" (a). Summary: Bacteria typically contain a single circular free DNA molecule that resides in the cytoplasm of the bacterial cell. This circular DNA contains the genetic information necessary for the bacterium's functions and is distinct from the membrane-bound nucleus found in eukaryotic cells. The double helical structure of DNA is a fundamental feature of all DNA, regardless of the organism.

175. Which one of the following statement about lichens is wrong?

• A. These grow very rapidly (2 cm per day).
• B. They show fungal and algal symbiotic relationships.
• C. Some of its species are eaten by reindeers.
• D. These are pollution indicators.

Explanation: The incorrect statement about lichens is a. These grow very rapidly (2 cm per day). Let's explain each option and provide more details: These grow very rapidly (2 cm per day) (a): This statement is incorrect. Lichens are known for their slow growth, and they typically grow much more slowly than 2 cm per day. Lichens are often used as indicators of environmental conditions, such as air quality, precisely because they grow slowly and are sensitive to environmental changes. They show fungal and algal symbiotic relationships (b): This statement is correct. Lichens are composite organisms consisting of a mutualistic relationship between a fungal partner (mycobiont) and an algal or cyanobacterial partner (photobiont). Some of its species are eaten by reindeers (c): This statement is correct. Lichens are an important food source for some animals, including reindeer, caribou, and certain insects. Lichens provide a winter food source for these animals in regions with limited vegetation. These are pollution indicators (d): This statement is correct. Lichens are often used as bioindicators of air quality and environmental pollution. Their sensitivity to air pollution, especially sulfur dioxide and heavy metals, makes them valuable in assessing environmental health. Correct Answer: The incorrect statement is "a. These grow very rapidly (2 cm per day)." Summary: Lichens are unique organisms that grow slowly and are composed of a mutualistic relationship between a fungal partner and an algal or cyanobacterial partner. Some lichen species are consumed by animals like reindeer, and lichens are used as bioindicators to assess environmental pollution and air quality due to their sensitivity to pollutants.

176. Mycorrhiza is correctly described as:

• A. Parasitic association between roots and some fungi.
• B. Symbiotic relationship between fungi and roots of some higher plants.
• C. Symbiosis of algae and fungi.
• D. Relation of ants with the stem of some trees.

Explanation: Mycorrhiza is correctly described as b. Symbiotic relationship between fungi and roots of some higher plants. Let's explain each option and provide more details: Parasitic association between roots and some fungi (a): This statement is not accurate. Mycorrhizal associations are typically mutualistic rather than parasitic. In mycorrhizal symbiosis, both the fungi and the plant benefit from the relationship. Symbiotic relationship between fungi and roots of some higher plants (b): This statement is correct. Mycorrhiza is a mutually beneficial association between certain fungi and the roots of many higher plants. The fungi assist in nutrient uptake, especially phosphorus and other minerals, while the plant provides the fungi with carbohydrates. Symbiosis of algae and fungi (c): This statement is not accurate. Mycorrhiza involves fungi and plant roots, not algae. The association you are describing is more closely related to lichens, which involve algae and fungi. Relation of ants with the stem of some trees (d): This statement is unrelated to mycorrhiza. It describes a different ecological interaction, which is not connected to the mycorrhizal symbiosis. Correct Answer: Mycorrhiza is correctly described as a "Symbiotic relationship between fungi and roots of some higher plants" (b). Summary: Mycorrhiza is a mutualistic association between certain fungi and the roots of many higher plants. In this symbiotic relationship, fungi assist plants in nutrient uptake, especially phosphorus and other minerals, while plants provide carbohydrates to the fungi. This mutually beneficial association is essential for the health and growth of many plants.

177. The tailed bacteriophages are:

• A. Motile on surface of bacteria.
• B. Non-motile.
• C. Motile on surface of plant leaves.
• D. Actively motile in water.

Explanation: The tailed bacteriophages are B. Non-motile.Let's explain each option and provide more details:Motile on the surface of bacteria (A):This statement is not accurate. Tailed bacteriophages are viruses that specifically infect and replicate within bacterial cells. They do not have the ability to move on the surface of bacteria.Non-motile (B):This is the correct answer. Tailed bacteriophages do not exhibit motility. They rely on random encounters with their bacterial hosts and do not have the ability to actively move or swim.Motile on the surface of plant leaves (C):This statement is not related to tailed bacteriophages, which are viruses that infect bacteria, not plants.Actively motile in water (D):Tailed bacteriophages are not actively motile in water. They are passive particles that rely on diffusion and random encounters to come into contact with their bacterial hosts.Correct Answer: The tailed bacteriophages are "Non-motile" (B).Summary:Tailed bacteriophages are non-motile viruses that infect bacterial cells. They do not possess the ability to move actively on the surface of bacteria or in the environment. Instead, they rely on chance encounters with their bacterial hosts for the infection and replication process.

178. A large number of organic compounds can be decomposed by:

• A. Azotobacter
• B. Chemolithotrophs
• C. Mycoplasma
• D. Pseudomonas

Explanation: Let's explain each option individually: a) Azotobacter: Azotobacter is a genus of free-living, nitrogen-fixing bacteria. While they play an essential role in nitrogen fixation by converting atmospheric nitrogen into a usable form for plants, they are not primarily known for their ability to decompose a large number of organic compounds. Their main significance lies in their contribution to nitrogen cycling and plant growth. b) Chemolithotrophs: This option is correct. Chemolithotrophs are organisms, including certain bacteria and archaea, that can decompose a large number of organic compounds using inorganic substances as a source of energy. These organisms derive their energy from the oxidation of inorganic compounds, such as ammonia, nitrite, sulfur, iron, or hydrogen, rather than organic carbon sources. They are essential players in various biogeochemical cycles, such as the nitrogen, sulfur, and iron cycles, as they help decompose and recycle a wide range of organic compounds in the environment. c) Mycoplasma: Mycoplasma is a genus of bacteria that are characterized by their small size and lack of a cell wall. While they can cause various diseases in animals and plants, they are not typically associated with decomposing a large number of organic compounds. Mycoplasma species are more commonly known for their parasitic or pathogenic nature. d) Pseudomonas: Pseudomonas is a diverse genus of bacteria that includes many species capable of breaking down a wide range of organic compounds. They are well-known for their metabolic versatility and ability to degrade various complex organic molecules, such as hydrocarbons, aromatic compounds, and pollutants. Some Pseudomonas species are valuable in bioremediation, where they help clean up environmental contamination by breaking down harmful substances. In summary, the correct answer is b) Chemolithotrophs. These organisms can decompose a large number of organic compounds using inorganic substances as a source of energy. While Pseudomonas can also decompose organic compounds, chemolithotrophs have a broader ability to break down various organic substances using inorganic compounds for energy.

179. Tobacco mosaic virus (TMV) genes are:

• A. Single stranded RNA
• B. Double stranded DNA
• C. Proteinaceous
• D. Double stranded RNA

Explanation: Let's explain each option individually:a) Single-stranded RNA:This option is correct. The genes of the Tobacco mosaic virus (TMV) are composed of single-stranded RNA (ribonucleic acid). TMV is a plant virus known for causing the tobacco mosaic disease, which affects various plants, including tobacco, tomatoes, peppers, and other members of the Solanaceae family. The RNA genome of TMV encodes the genetic information necessary for the virus to replicate and produce its proteins during the infection process.b) Double-stranded DNA:Double-stranded DNA (deoxyribonucleic acid) is a genetic material found in most living organisms, including plants, animals, and bacteria. However, TMV is not a DNA virus; it is an RNA virus with a single-stranded RNA genome.c) Proteinaceous:The term "proteinaceous" refers to something that is primarily composed of proteins. While TMV is a virus made up of proteins and RNA, the genes of TMV are specifically composed of single-stranded RNA, not just proteins.d) Double-stranded RNA:This option is not correct. TMV does not have a double-stranded RNA genome. Instead, its genome consists of a single-stranded RNA molecule.In summary, the correct answer is a) Single-stranded RNA. The genes of the Tobacco mosaic virus (TMV) are composed of single-stranded RNA. This RNA genome contains the instructions for the virus to infect host plant cells, replicate, and produce new viral particles, leading to the characteristic mosaic-like patterns and other symptoms observed in infected plants.

180. Phylogenetic classification is one which is based on:

• A. Overall similarities
• B. Utilitarian system
• C. Habits of plants
• D. Common evolutionary descent

Explanation: Let's explain each option individually: a) Overall similarities: Phylogenetic classification is not solely based on overall similarities between organisms. While similarities are considered in phylogenetics, it is essential to differentiate between homologous traits (traits inherited from a common ancestor) and analogous traits (traits that have evolved independently due to similar environmental pressures). Phylogenetic classification aims to reconstruct evolutionary relationships based on shared, homologous characteristics that reflect common ancestry. b) Utilitarian system: The term "utilitarian system" is not commonly used in the context of biological classification. It does not specifically refer to a method of classification based on evolutionary relationships or common descent. c) Habits of plants: Phylogenetic classification is not solely based on the habits or ecological characteristics of plants or other organisms. While ecological traits and adaptations can provide valuable information about the biology of organisms, they are not the primary focus of phylogenetic classification. Instead, phylogenetics aims to establish evolutionary relationships and construct evolutionary trees that depict the branching patterns of organisms over time. d) Common evolutionary descent: This option is correct. Phylogenetic classification is based on the principle of common evolutionary descent. It seeks to organize organisms into groups based on their evolutionary history and shared ancestry. By analyzing homologous traits (similarities inherited from a common ancestor), scientists can construct phylogenetic trees that represent the evolutionary relationships between different organisms. The tree's branching patterns reflect the divergence of lineages over time, showing the common descent and relatedness among different species or groups of organisms. In summary, the correct answer is d) Common evolutionary descent. Phylogenetic classification is based on reconstructing the evolutionary relationships between organisms by analyzing shared, homologous characteristics, and depicting their common ancestry through the construction of phylogenetic trees.