Title Ex- 2 Biological Classification (Q-Sol-Ans).pdf ✅

21 BIOLOGICAL CLASSIFICATION EXERCISE – 2: Previous Year Questions 1. Which of the following statements is correct? (NEET 2021) (a) Fusion of two cells is called Karyogamy. (b) Fusion of protoplasms between two motile or non- motile gametes is called plasmogamy. (b) Organisms that depend on living plants are called saprophytes. (d) Some of the organisms can fix atmospheric nitrogen in specialized cells called sheath cells. Ans. (b) Sol. -Fusion of protoplasms between two motile or non- motile gametes is called plasmogamy. -Fusion of two nuclei is called karyogamy. -Heterotrophic organisms that absorb soluble organic matter from dead substrates are called saprophytes, e.g., Fungi. -Some of the organisms can fix atmospheric nitrogen in specialized cells called heterocysts, e.g., Nostoc and Anabaena. 2. Which of the following is correct about viroids? (NEET 2020) (a) They have DNA with protein coat. (b) They have free DNA without protein coat. (c) They have RNA with protein coat. (d) They have free RNA without protein coat. Ans. (d) Sol. Viroids are the infectious particles smaller than viruses. They differ from viruses as they have free RNA without the protein coat or capsid. Potato spindle tuber disease is a disease caused by a viroids. 3. Which of the following statements is incorrect? (NEET 2019) (a) Claviceps is a source of many alkaloids and LSD. (b) Conidia are produced exogenously and ascospores endogenously. (c) Yeasts have filamentous bodies with long thread- like hyphae. (d) Morels and truffles are edible delicacies. Ans. (c) Sol. Yeast is a unicellular sac fungus (belongs to Ascomycota). It lacks filamentous structure or hyphae. 4. Which of the following statements is incorrect? (NEET 2019) (a) Viruses are obligate parasites (b) Infective constituent in viruses is the protein coat (c) Prions consist of abnormally folded proteins (d) Viroids lack a protein coat Ans. (b) Sol. Infective constituent in viruses is their genetic material which is either DNA or RNA. This genetic material when enters the host cells, takes control of its genome by integrating in it and causes viral infection. 5. Match Column –I with Column – II (NEET 2019) Column - I Column – II (p) Saprophyte (i) Symbiotic association of fungi with plant roots (q) Parasite (ii) Decomposition of dead organic materials (r) Lichens (iii) Living on living plants or animals (s) Mycorrhiza (iv) Symbiotic association of algae and fungi Choose the correct answer from the options given below: (a) p → (iii); q → (ii); r → (i); s → (iv) (b) p → (ii); q → (i); r → (iii); s → (iv) (c) p → (ii); q → (iii); r → (iv); s → (i) (d) p → (i); q → (ii); r → (iii); s → (iv) Ans. (c) Sol. -Saprophytes obtain their food by decomposing dead organic materials, like fallen leaves, vegetables, animal excreta, etc. -Parasites grow on/in other living plants and animals to obtain nourishment.
BIOLOGICAL CLASSIFICATION 22 -Lichens are symbiotic associations i.e., mutually useful associations, between algae and fungi. -Mycorrhiza is the symbiotic association of fungi with plant roots. 6. Which among the following is not a prokaryote? (NEET 2018) (a) Nostoc (b) Mycobacterium (c) Saccharomyces (d) Oscillatoria Ans. (c) Sol. Prokaryotes are the organism that does not possess a true nucleus and double membrane-bounded organelles. Nostoc, Mycobacterium and Oscillatoria are prokaryotes. Saccharomyces (Yeast) is eukaryote belonging to Kingdom Fungi. Eukaryotes have a well-defined nucleus with a nuclear membrane and membrane bound organelles. 7. Select the wrong statement: (NEET 2018) (a) Pseudopodia are locomotory and feeding structures in sporozoans (b) Mushrooms belong to basidiomycetes (c) Cell wall is present in members of fungi and plantae (d) Mitochondria are the powerhouse of the cell in all kingdoms except Monera Ans. (a) Sol. -Pseudopodia are the finger-like projections found in Amoeboid protozoans such as, Amoeba. They help in moving and capturing the prey. Locomotory structures are absent in sporozoans. -Mushrooms belong to class Basidiomycetes (Kingdom Fungi), e.g., Agaricus. -Cell wall is present in the members of both Kingdom Fungi and Plantae. Fungal cell wall is made up of chitin and cell wall of the plant is made up of cellulose and hemicellulose. -Mitochondria are called the powerhouse of the cell because they are associated with cellular respiration. They are present only in eukaryotes and absent in prokaryotes. 8. After karyogamy followed by meiosis, spores are produced exogenously in (NEET 2018) (a) Agaricus (b) Alternaria (c) Neurospora (d) Saccharomyces Ans. (a) Sol. In basidiomycetes (Kingdom Fungi), karyogamy and meiosis takes place in basidium and produce four spores exogenously. These are known as basidiospores, e.g., Agaricus. In Alternaria, Neurospora and Saccharomyces spores are produced endogenously. 9. Ciliates differ from all other protozoans in (NEET 2018) (a) Using pseudopodia for capturing prey (b) Having a contractile vacuole for removing excess water (c) Using flagella for locomotion (d) Having two types of nuclei Ans. (d) Sol. The protozoan group which is characterized by the presence of hair-like structures known as cilia are called ciliates. Cilia are used for the locomotion and food gathering. The characters which differentiate ciliates from all other protozoans is having two types of nuclei (somatic macronucleus and germline micronucleus). 10. Which of the following organisms are known as chief producers in the oceans? (NEET 2018) (a) Cyanobacteria (b) Diatoms (c) Dinoflagellates (d) Euglenoids Ans. (b) Sol. Phytoplankton are the primary producers in the aquatic ecosystem. They consist of two groups diatoms and dinoflagellates. Diatoms are known as chief producers in the ocean. The food chain in the marine ecosystem and oxygen production depends mainly on them. 11. Which among the following are the smallest living cells, known without a definite cell wall, pathogenic to plants as well as animals and can survive without oxygen? (NEET 2017) (a) Bacillus (b) Pseudomonas (c) Mycoplasma (d) Nostoc Ans. (c) Sol. Mycoplasma are the smallest living cells which do not possess a definite cell wall. They have cell membrane as the outermost covering. They are
23 BIOLOGICAL CLASSIFICATION pathogenic to plants as well as animals. They can survive without oxygen. 12. Viroids differ from viruses in having (NEET 2017) (a) DNA molecules with protein coat (b) DNA molecules without protein coat (c) RNA molecules with protein coat (d) RNA molecules without protein coat Ans. (d) Sol. Viruses are obligate intracellular parasites. They are nucleoprotein particles having nuclear material (DNA or RNA) and a protein envelope. Viroids are the infectious particles having only RNA and without any protein coat. 13. Which of the following statements is wrong for viroids? (NEET 2016) (a) They lack a protein coat (b) They are smaller than viruses (c) They cause infections (d) Their RNA is of high molecular weight Ans. (d) Sol. Viroids are the particles with RNA as a genetic material but does not contain protein as outer covering. They are infectious, non-protein coding, rod-like structures, with low-molecular-weight RNA (single-stranded, closed circular). 14. One of the major components of cell wall of most fungi is (NEET 2016) (a) Chitin (b) Peptidoglycan (c) Cellulose (d) Hemicellulose Ans. (a) Sol. The cell wall of fungi is composed of carbohydrate polymers with glycoproteins. The major three components which are found in the fungal cell walls are β-glucans (glucose polymer), chitin (a polymer of N-acetylglucosamine) and mannans. In these three- component, chitin tends to dominate and mostly provide structural strength to the cell wall. 15. Chrysophytes, euglenoids, dinoflagellates and slime moulds are included in the kingdom (NEET 2016) (a) Animalia (b) Monera (c) Protista (d) Fungi Ans. (c) Sol. According to the Five-kingdom classification proposed by R.H. Whittaker, Kingdom Protista comprises of unicellular and organisms. They can be autotrophic or heterotrophic. Primarily, they are aquatic. The Kingdom Protista is divided into Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds. 16. The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals, include the (NEET 2016) (a) Halophiles (b) Thermoacidophiles (c) Methanogens (d) Eubacteria Ans. (c) Sol. Methanogens are prokaryotes that produce biogas from the dung of ruminant animals. Methanogens are present in the gut of the ruminant animals (like cows and buffaloes). The produced biogas is methane. It is a metabolic by-product produced by methanogens in hypoxic conditions. 17. Which one of the following is wrong for fungi? (NEET 2016) (a) They are eukaryotic (b) All fungi possess a purely cellulosic cell wall (c) They are heterotrophic (d) They are both unicellular and multicellular Ans. (b) Sol. Fungi are unicellular or multicellular eukaryotes, with a heterotrophic (saprophytic or parasitic) mode of nutrition. They possess a chitinous cell wall, which is a characteristic feature of fungi. Whereas, cellulosic cell wall is found in plants. 18. Methanogens belong to (NEET 2016) (a) Eubacteria (b) Archaebacteria (c) Dinoflagellates (d) Slime moulds Ans. (b) Sol. Archaebacteria are a primitive group of bacteria known to live in some of the harshest habitats such as extreme salty areas, hot springs, and marshy areas. Methanogens are archaebacteria that produce methane under anaerobic conditions, e.g., Methanobacterium, Methanococcus. They belong to Kingdom Monera.
BIOLOGICAL CLASSIFICATION 24 19. Select the wrong statement. (NEET 2016) (a) The walls of diatoms are easily destructible (b) ‘Diatomaceous earth’ is formed by the cell walls of diatoms (c) Diatoms are chief producers in the oceans (d) Diatoms are microscopic and float passively in water Ans. (a) Sol. Phytoplankton are the primary producers in the aquatic ecosystem. They consist diatoms which are the chief producers in the ocean. They are microscopic and float passively in water. Their cell walls are made up of silica which is a non- destructible material. Hence, cell wall deposits of diatoms overs billions of years have resulted in the formation of diatomaceous earth. 20. Which one of the following statements is wrong? (NEET 2016) (a) Cyanobacteria are also called blue-green algae. (b) Golden algae are also called desmids. (c) Eubacteria are also called false bacteria. (d) Phycomycetes are also called algal fungi. Ans. (c) Sol. -Cyanobacteria are also called blue green algae and it has photosynthetic capability. - Golden algae are also called desmids. They belong to group Chrysophytes. - Bacteria are divided into two types, eubacteria and archaebacteria. Eubacteria are also called true bacteria. They are characterised by the presence of a rigid cell wall, and if motile, a flagellum -Phycomycetes are also referred to as algal fungi. 21. Choose the wrong statement. (AIPMT 2015) (a) Yeast is unicellular and useful in fermentation (b) Penicillium is multicellular and produces antibiotics (c) Neurospora is used in the study of biochemical genetics (d) Morels and truffles are poisonous mushrooms Ans. (d) Sol. -Yeast is a unicellular fungus and in anaerobic conditions, they convert sugar into alcohol with the release of carbon dioxide so that it is used in the fermentation process. -Penicillium is a multicellular fungus belonging to ascomycetes and antibiotic Penicillin is produced from it. -Neurospora is used in genetics and biochemical studies. -Morels and truffles belong to Ascomycetes and produce an edible fruiting body. These are considered delicacies. 22. Cell wall is absent in- (AIPMT 2015) (a) Nostoc (b) Aspergillus (c) Funaria (d) Mycoplasma Ans. (d) Sol. Mycoplasma is the smallest living cell which does not possess a definite cell wall, but has cell membrane as its outermost covering. Mycoplasma are the members of the Kingdom Monera. 23. In which group of organisms, the cell walls form two thin overlapping shells which fit together? (AIPMT 2015) (a) Slime moulds (b) Chrysophytes (c) Euglenoids (d) Dinoflagellates Ans. (b) Sol. The group Chrysophytes (Kingdom Protista) includes diatoms and golden algae (desmids) The cell wall of diatoms forms two thin overlapping shells (frustules) which fit together like a soapbox. They are known as the chief producers in the ocean. 24. The imperfect fungi which are decomposers of litter and help in mineral cycling belong to: (AIPMT 2015) (a) Ascomycetes (b) Deuteromycetes (c) Basidiomycetes (d) Phycomycetes Ans. (b) Sol. The imperfect fungi which are decomposers of litter and help in mineral cycling belong to deuteromycetes. They do not fit in the common taxonomic classification due to the absence or not known sexual stages in their life cycle. So, they are called as imperfect fungi, e.g., Colletotrichum, Helminthosporium.