Biological Classification

31 NEET-UG practice questions on Biological Classification, part of Botany. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Medium

   A saprophytic fungus has branched, septate mycelium and reproduces only by conidia. No sexual stage has been found. In which class should it be placed?

   1. ABasidiomycetes
   2. BDeuteromycetes
   3. CAscomycetes
   4. DPhycomycetes

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   Answer: B · Deuteromycetes

   Fungi in which only the asexual or vegetative phases are known are placed in Deuteromycetes, the imperfect fungi. Their mycelium is septate and branched, and they reproduce by conidia.

   • A: Basidiomycetes form basidiospores in a sexual cycle.
   • C: Ascomycetes form ascospores in a sexual cycle.
   • D: Phycomycetes have aseptate, coenocytic mycelium.

   Remember this

   When the sexual stage of a deuteromycete is found, it is usually moved to Ascomycetes or Basidiomycetes.

2. Question 2 · Medium

   Regarding the two partners of a lichen and where lichens grow, which claim is NOT correct?

   1. ALichens do not grow in polluted areas
   2. BThe fungal partner gives shelter and absorbs water and minerals
   3. CThe fungal partner prepares food for the alga by photosynthesis
   4. DThe algal partner prepares food for the fungus

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   Answer: C · The fungal partner prepares food for the alga by photosynthesis

   A lichen is a mutually useful association of an alga and a fungus. The phycobiont is autotrophic and prepares food, while the heterotrophic mycobiont provides shelter and absorbs mineral nutrients and water.

   • A: This is correct because lichens are sensitive pollution indicators.
   • B: This is a correct statement of the role of the mycobiont.
   • D: This is a correct statement because the alga is the autotrophic partner.

   Remember this

   Phycobiont makes food, mycobiont gives shelter and absorption, and lichens are good pollution indicators.

3. Question 3 · Easy

   Which archaebacteria live in the gut of ruminants and produce methane during biogas formation?

   1. AMethanogens
   2. BCyanobacteria
   3. CThermoacidophiles
   4. DHalophiles

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   Answer: A · Methanogens

   Methanogens occur in marshy areas and in the gut of ruminant animals such as cows and buffaloes. They produce methane in the dung of these animals.

   • B: Cyanobacteria are photosynthetic eubacteria, not archaebacteria.
   • C: Thermoacidophiles live in hot springs.
   • D: Halophiles live in extreme salty areas.

   Remember this

   Halophiles live in salty areas, thermoacidophiles in hot springs and methanogens in marshes and ruminant guts.

4. Question 4 · Medium

   Arrange these events in the sexual cycle of a basidiomycete such as Agaricus in the correct sequence. A. Meiosis forms basidiospores B. Karyogamy occurs in the basidium C. Two somatic cells of different strains fuse D. A dikaryotic structure forms

   1. AC, D, B, A
   2. BC, D, A, B
   3. CD, C, B, A
   4. DC, B, D, A

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   Answer: A · C, D, B, A

   Sex organs are absent, so plasmogamy occurs by fusion of two somatic cells of different strains. This gives a dikaryotic structure that ultimately forms the basidium, in which karyogamy and then meiosis take place, producing four basidiospores.

   • B: Meiosis needs the diploid nucleus formed by karyogamy first.
   • C: The dikaryon cannot form before the two cells fuse.
   • D: Karyogamy cannot happen before the dikaryotic stage.

   Remember this

   The fungal sequence is plasmogamy, dikaryon, karyogamy, then meiosis to form spores.

5. Question 5 · Easy

   Bacteria with a comma shape are called

   1. ABacillus
   2. BVibrio
   3. CSpirillum
   4. DCoccus

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   Answer: B · Vibrio

   Bacteria are grouped into four shapes: spherical coccus, rod-shaped bacillus, comma-shaped vibrio and spiral spirillum.

   • A: Bacillus is rod-shaped.
   • C: Spirillum is spiral.
   • D: Coccus is spherical.

   Remember this

   Coccus is spherical, bacillus rod-shaped, vibrio comma-shaped and spirillum spiral.

6. Question 6 · Hard

   Match List-I with List-II. List-I (fungus) A. Albugo B. Neurospora C. Puccinia D. Colletotrichum List-II (feature of its class) I. Only conidia known, with no sexual stage recorded II. Basidiospores formed exogenously on a basidium III. Ascospores formed endogenously in a sac IV. Aseptate coenocytic mycelium with zygospores

   1. AA-IV, B-III, C-I, D-II
   2. BA-III, B-IV, C-II, D-I
   3. CA-IV, B-III, C-II, D-I
   4. DA-IV, B-II, C-III, D-I

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7. Question 7 · Easy

   The infectious agent of potato spindle tuber disease is made up of

   1. AFree RNA without a protein coat
   2. BRNA enclosed in a protein coat
   3. CAbnormally folded protein alone
   4. DDouble-stranded DNA inside a capsid

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8. Question 8 · Medium

   Assertion A: Diatom cell walls pile up over billions of years as a soil-like deposit at the bottom of the water. Reason R: The silica embedded in diatom cell walls makes them indestructible. Choose the correct answer.

   1. ABoth A and R are correct but R is not the correct explanation of A
   2. BBoth A and R are correct and R is the correct explanation of A
   3. CA is not correct but R is correct
   4. DA is correct but R is not correct

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9. Question 9 · Hard

   Consider these statements on acellular infectious agents. A. Viroids have RNA of low molecular weight. B. Prions consist of abnormally folded protein. C. Bacteriophages are usually double-stranded DNA viruses. D. Viruses that infect plants generally have double-stranded DNA. Which statements are correct?

   1. AB, C and D only
   2. BA and B only
   3. CA, C and D only
   4. DA, B and C only

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10. Question 10 · Medium

    Given below are two statements: Statement I: The cell walls of dinoflagellates are embedded with silica and form diatomaceous earth. Statement II: Euglenoids have a protein-rich pellicle in place of a cell wall. Choose the correct answer.

    1. ABoth Statement I and Statement II are correct
    2. BBoth Statement I and Statement II are incorrect
    3. CStatement I is correct but Statement II is incorrect
    4. DStatement I is incorrect but Statement II is correct

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11. Question 11 · Medium

    Assertion A: Bacteriophages are usually double-stranded DNA viruses. Reason R: Viruses that infect plants generally have double-stranded DNA. Choose the correct answer.

    1. ABoth A and R are correct and R is the correct explanation of A
    2. BA is correct but R is not correct
    3. CBoth A and R are correct but R is not the correct explanation of A
    4. DA is not correct but R is correct

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12. Question 12 · Hard

    Read these statements about Monera. A. Archaebacteria have the same cell wall structure as eubacteria. B. Mycoplasma lacks a cell wall, is among the smallest living cells known and can survive without oxygen. C. In Nostoc and Anabaena, specialised heterocysts fix atmospheric nitrogen. D. Chemosynthetic autotrophic bacteria oxidise substances such as nitrites and ammonia and use the energy released to make ATP. Which statements are correct?

    1. AA, B and C only
    2. BB, C and D only
    3. CA, B, C and D
    4. DC and D only

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13. Question 13 · Medium

    Match List-I with List-II. List-I (Protist group) A. Euglenoids B. Dinoflagellates C. Slime moulds D. Ciliated protozoans List-II (Feature) I. Plasmodium that forms fruiting bodies bearing spores with true walls II. Protein-rich pellicle that keeps the body flexible III. Gullet opening to the outside of the cell surface IV. Stiff cellulose plates; some cause red tides

    1. AA-II, B-I, C-IV, D-III
    2. BA-II, B-IV, C-III, D-I
    3. CA-II, B-IV, C-I, D-III
    4. DA-IV, B-II, C-I, D-III

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14. Question 14 · Easy

    The five kingdom classification, with Monera, Protista, Fungi, Plantae and Animalia, was proposed in 1969 by

    1. ACarl Woese
    2. BAristotle
    3. CCarolus Linnaeus
    4. DR.H. Whittaker

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15. Question 15 · Medium

    Protists whose cell walls are embedded with silica, fit together like a soap box and pile up over billions of years as 'diatomaceous earth' belong to the group

    1. ASlime moulds
    2. BEuglenoids
    3. CDinoflagellates
    4. DChrysophytes

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16. Question 16 · Easy

    Which human disease is caused by a prion, an abnormally folded protein?

    1. ABacterial meningitis
    2. BCreutzfeldt-Jakob disease
    3. CJapanese encephalitis
    4. DAcquired immunodeficiency syndrome

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17. Question 17 · Hard

    Read the following statements about fungi. A. In basidiomycetes, sex organs are absent and plasmogamy occurs by fusion of two vegetative cells of different strains. B. In ascomycetes, the asexual spores called conidia are produced endogenously inside sacs. C. Basidiospores are produced exogenously on the basidium after karyogamy and meiosis. D. Claviceps and Neurospora are members of the ascomycetes. Which statements are correct?

    1. AA and D only
    2. BA, C and D only
    3. CB, C and D only
    4. DA, B and C only

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18. Question 18 · Medium

    Given below are two statements: Statement I: The plasmodium of a slime mould forms fruiting bodies bearing spores only when conditions are favourable. Statement II: Slime mould spores have true walls, are extremely resistant and can survive for many years. Choose the correct answer.

    1. AStatement I is incorrect but Statement II is correct
    2. BBoth Statement I and Statement II are incorrect
    3. CStatement I is correct but Statement II is incorrect
    4. DBoth Statement I and Statement II are correct

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19. Question 19 · Medium

    Assertion A: Archaebacteria can live in some of the most extreme habitats, such as hot springs and extreme salty areas. Reason R: Archaebacteria have a cell wall structure different from that of other bacteria. Choose the correct answer.

    1. AA is not correct but R is correct
    2. BA is correct but R is not correct
    3. CBoth A and R are correct but R is not the correct explanation of A
    4. DBoth A and R are correct and R is the correct explanation of A

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20. Question 20 · Medium

    Match List-I with List-II. List-I (Agent) A. Tobacco mosaic virus B. Prion C. Viroid D. Bacteriophage List-II (Genetic material or nature) I. Usually double-stranded DNA II. Single-stranded RNA inside a protein coat III. Free RNA of low molecular weight, with no protein coat IV. Abnormally folded protein Choose the correct answer.

    1. AA-III, B-IV, C-II, D-I
    2. BA-II, B-I, C-III, D-IV
    3. CA-II, B-IV, C-III, D-I
    4. DA-I, B-IV, C-III, D-II

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21. Question 21 · Hard

    Examine these statements about protozoans. A. All protozoans are heterotrophs and live as predators or parasites. B. Plasmodium, the malarial parasite, belongs to the sporozoans. C. In Paramoecium, rows of cilia steer water laden with food into the gullet. D. Trypanosoma, which causes sleeping sickness, is an amoeboid protozoan. Which of the statements given above are correct?

    1. AA, B and D only
    2. BB and C only
    3. CA, C and D only
    4. DA, B and C only

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22. Question 22 · Medium

    Four fungi named in NCERT are listed below. Match each with its class. List-I (Fungus) A. Rhizopus B. Claviceps C. Ustilago D. Colletotrichum List-II (Class) I. Basidiomycetes II. Deuteromycetes III. Phycomycetes IV. Ascomycetes Choose the correct answer from the options given below.

    1. AA-IV, B-III, C-I, D-II
    2. BA-III, B-IV, C-I, D-II
    3. CA-III, B-I, C-IV, D-II
    4. DA-III, B-IV, C-II, D-I

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23. Question 23 · Hard

    A soil organism has a cell wall but no membrane-bound nucleus. It obtains energy for making ATP by oxidising ammonia, and it does not carry out photosynthesis. To which group does it belong?

    1. AHeterotrophic bacteria
    2. BChemosynthetic autotrophic bacteria
    3. CCyanobacteria
    4. DMethanogens

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24. Question 24 · Medium

    Plant viruses usually have single-stranded RNA, while animal viruses may have RNA or DNA. What do bacterial viruses, the bacteriophages, usually contain?

    1. AFree RNA without a protein coat
    2. BSingle-stranded RNA
    3. CDouble-stranded DNA
    4. DProtein without any nucleic acid

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25. Question 25 · Medium

    Arrange the following steps in the discovery of viruses and viroids in chronological order. A. W.M. Stanley showed that viruses could be crystallised, the crystals consisting largely of proteins. B. T.O. Diener discovered a new infectious agent, smaller than viruses, causing potato spindle tuber disease. C. D.J. Ivanowsky recognised that the agent of mosaic disease of tobacco was smaller than bacteria. D. M.W. Beijerinek called the infectious extract of infected tobacco 'contagium vivum fluidum'. Choose the correct order.

    1. AC, D, A, B
    2. BC, A, D, B
    3. CC, D, B, A
    4. DD, C, A, B

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