Biological Classification MCQ Quiz in मल्याळम - Objective Question with Answer for Biological Classification - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is a - iv, b - iii, c - ii, d - i

Explanation:

• (a) 1971 - (iv) Viroids: Viroids were discovered in 1971 by Theodor Diener. These are infectious agents composed solely of a short strand of circular, single-stranded RNA without a protein coat, which is in contrast to viruses.
• (b) 1969 - (iii) R.H. Whittaker: In 1969, Robert H. Whittaker proposed the five-kingdom classification system of living organisms, which includes Monera, Protista, Fungi, Plantae, and Animalia.
• (c) 1892 - (ii) Dmitri Ivanowsky: In 1892, Dmitri Ivanowsky discovered that tobacco mosaic disease could be transmitted by an agent smaller than bacteria, which led to the identification of viruses.
• (d) 1898 - (i) Infectious living fluid: In 1898, Martinus Beijerinck coined the term "virus" and described it as an infectious living fluid, furthering the understanding of viral diseases.

Concept:

• According to R.H. Whittaker's Five Kingdom system, the living organisms are divided into the following Kingdoms - 
  • Kingdom Monera
  • Kingdom Protista
  • Kingdom Plantae
  • Kingdom Fungi
  • Kingdom Animalia
• Kingdom Monera includes unicellular prokaryotic organisms. E.g.- Salmonella
• Kingdom Protista includes unicellular eukaryotic organisms. E.g.- Amoeba
• Kingdom Plantae includes multicellular eukaryotic organisms. Includes autotrophs, semi-autotrophs, and insectivorous plants.
• Kingdom Fungi include multicellular eukaryotic organisms. These are mainly heterotrophs. E.g.- Rhizopus
• Kingdom Animalia includes multicellular eukaryotes that are heterotrophs. These organisms have adapted to holozoic nutrition. E.g.- Human beings

Explanation:

• Virus - 
  • ​Viruses are acellular or non-cellular organisms that have either DNA or RNA as their genetic material.
  • They have an inert crystalline structure outside the living cell.
  • The genetic material could be either a single or double-stranded RNA or double-stranded DNA.
  • Viruses show the presence of a protein coat called capsid surrounding their genetic material.
  • Thus the body of a virus consists of just a strand of nucleic acid (genetic material) surrounded by a protein coat.
  • Viruses are non-living organisms that require a host body to duplicate. They are obligate parasites.
  • Once inside a host cell, they take charge of the cellular machinery and duplicate themselves.
  • Viruses are not considered a "truly living" organism as they do not possess a cellular structure i.e. they are acellular.
  • Since they are not considered living organisms, viruses were not placed in any of the Kingdoms as proposed by R.H. Whittaker.
  • Viruses are pathogenic organisms that cause several diseases in living organisms including humans.
  • AIDS, mumps, chicken pox, etc. are some of the diseases caused by viruses in humans.
  • In plants, leaf rolling and curling, yellowing and vein clearing, dwarfing and stunted growth, etc. are caused due to viruses.

So from the above-given information, the correct answer is option 4.

correct answer is Fungi.

Key Points

• Mycology is the study of fungus organisms that cause disease in humans.
• Mycology also has important applications in the dairy, wine, and baking industries and in the production of dyes and inks..
• study of fungi  includes the mushrooms and yeasts..
• Mycology helps to differentiate between useful and harmful fungi and how the crops with fungal infections can be treated.

Additional Information

• Mycological research has led to the development of such antibiotic drugs as penicillin, streptomycin, and tetracycline, as well as other drugs, including statins (cholesterol-lowering drugs). 
• Fungi can also breakdown complex substances to produce carbon dioxide.
• Yeast is another form of fungi which is used in brewing, distilling and bread making.
• Fungi act as major pests for many crops but also live in symbiotic association with many plants and provide them with nutrition and water.

Important Points

• The study of algae is called phycology. 
• Virology is the study of viruses and virus-like agents
• The study of bacteria is known as bacteriology.

• A saprophyte is an organism that uses decaying matter as its food source.
• The fungi kingdom is a group of organisms that feed on decaying matter
• One distinguishing feature is that their cell walls are made of a substance known as chitin.

Concept:

• Greek word phainein, which means "to appear," is the root of the word "phenetic."
• Based on quantifiable similarities and differences, species are categorized phonetically.
• Taximetrics is another name used for phenetic classification.

Explanation:

• Phenetic classification is based on observable characteristics of an existing organism, that is, morphology or other observable traits, irrespective of their phylogeny or evolutionary relation.
• Cladistics is a method of reconstructing evolutionary trees. It gives an idea about the ancestral lineage of existing organisms.
• Any visual representation that describes a taxonomic system in the form of a tree, such as a drawing or a diagram, is referred to as a "dendrogram" in numerical taxonomy.
• A dendrogram is a two-dimensional diagram that represents a relationship tree in general, regardless of the type of relationship.

So, the correct answer is Option 3: Observable characteristics of existing organisms.

Key Points

• All single-celled eukaryotes are placed under Protista. It can be broadly classified into 5 types: Chrysophytes, Dinoflagellates, Euglenoids, Slime molds, and Protozoans
• This kingdom forms a link with the others dealing with plants, animals, and fungi.
• Being eukaryotes, the protistan cell body contains a well-defined nucleus and other membrane-bound organelles. Some have flagella or cilia.
• Protists reproduce asexually and sexually by a process involving cell fusion and zygote formation

• Dinoflagellate belongs to the kingdom Protista.
• It is a unicellular eukaryote.
• It lives in water, land, and as a parasite.
• Dinoflagellate is marine and photosynthetic.
• It bears two cilia, one lies longitudinally and the other transversely in a furrow between the wall plates.
• It causes red tides in the sea.
• It releases toxins, and thus the organisms inhabiting the areas die.
• Gonyaulax is an example.
• The correct answer is Option 4: (a),(b), and (c) only.

The correct answer is It is the smallest living cell known and lacks a cell wall.

Concept:

• Mycoplasma is a genus of bacteria that are characterized by the absence of a cell wall, making them unique among prokaryotes.
• They are the smallest free-living organisms known, capable of self-replication.
• The absence of a cell wall allows them to be resistant to antibiotics that target cell wall synthesis, such as penicillin.

Explanation:

• Option 1: It is a type of bacteria that has a cell wall. This is incorrect because Mycoplasma lacks a cell wall, which is one of its defining characteristics.
• Option 2: It is the smallest living cell known and lacks a cell wall. This is correct. Mycoplasma is indeed the smallest living cell known and lacks a cell wall. This unique feature differentiates it from other bacteria.
• Option 3: It belongs to the Kingdom Protista. This is incorrect. Mycoplasma belongs to the Kingdom Monera (or Bacteria), not Protista.
• Option 4: It is used in the fermentation of beer. This is incorrect. Mycoplasma is not used in the fermentation of beer; yeast (a type of fungus) is typically used for this purpose.

Concept:

• R.H. Whittaker proposed the Five Kingdom System of Classification.
• According to R.H. Whittaker's Five Kingdom system, the living organisms are divided into the following Kingdoms - 
  • Kingdom Monera
  • Kingdom Protista
  • Kingdom Plantae
  • Kingdom Fungi
  • Kingdom Animalia
• Kingdom Protista includes all unicellular eukaryotic organisms.
• This Kingdom shows a link with the remaining eukaryotic Kingdoms - Fungi, Plantae, and Animalia.
• Chrysophytes, Dinoflagellates, Euglenoids. Slime molds and Protozoans are grouped under Kingdom Protista.
• Examples: Paramoecium, Euglena, Amoeba, Oodinium, etc.

Explanation:

Slime molds - 

• ​Slime molds are unicellular eukaryotic organisms belonging to the Kingdom Protista.
• They either live as a single cell or aggregate together to form multicellular organisms.
• They are saprophytic organisms. It obtains its nutrition by absorbing organic material.
• When food is available, slime molds exist as single-cell  fruiting bodies that bear spores at their tips.
• Whereas in scarcity of food slime molds form aggregates and live in colonies.
• The aggregates of slime molds formed are called plasmodium.
• Plasmodium slime molds may grow and spread over several feet.
• The plasmodium slime molds contain cytoplasm with an undivided plasma membrane.
• The cells do not have a cell wall and have a naked cytoplasm.
• The cytoplasm contains multiple nuclei.
• Slime molds are extremely resistant and can survive for many years even in adverse conditions.

So from the above-given information, the correct answer is option 4.

The correct answer is a and d

Explanation:

• a. True: Chemosynthetic bacteria play a significant role in recycling nutrients such as nitrogen, phosphorus, iron, and sulfur by converting these elements into forms that can be utilized by other organisms in the environment.
• b. False: Chemosynthetic bacteria are not heterotrophic bacteria. They are autotrophic bacteria that produce their own food using energy derived from the oxidation of inorganic substances, such as ammonia or sulfur compounds, rather than relying on organic substances.
• c. False: Chemosynthetic bacteria release energy by oxidizing inorganic substances, not organic substances. This oxidation process provides the energy required to produce organic molecules from carbon dioxide (CO₂).
• d. True: Chemosynthetic bacteria are crucial in nutrient cycling, as they help in the conversion and recycling of essential nutrients within ecosystems, maintaining ecological balance.

Therefore, the true statements are a and d.

The correct answer is 4 → 2 → 5 → 3 → 1

Explanation:

1. Germination of basidiospores (4):
   • The cycle begins when basidiospores, which are haploid, germinate.
   • These spores produce haploid mycelia.
2. Fusion of compatible hyphae (2):
   • When two compatible haploid mycelia meet, their hyphae fuse.
   • This process is called plasmogamy.
3. Formation of dikaryotic mycelium (5):
   • After fusion, the nuclei from each haploid hypha remain separate.
   • This creates a dikaryotic mycelium (two nuclei per cell).
4. Development of fruiting body (3):
   • Under suitable conditions, the dikaryotic mycelium develops into a fruiting body.
   • In mushrooms, this is the visible part we see above ground.
5. Formation of basidiospores (1):
   • Inside the fruiting body, specialized cells called basidia are formed.
   • In basidia, karyogamy (nuclear fusion) occurs, followed by meiosis.