Chapter 2: Biological Classification Assertion-Reason Questions | biology Class 11 CBSE

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 1

Logic Check

Assertion (A): Bacteria are the most metabolically diverse group of organisms on Earth. Reason (R): Bacteria can be photosynthetic autotrophs, chemosynthetic autotrophs, saprophytic heterotrophs, or parasitic heterotrophs.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 2

Logic Check

Assertion (A): Mycoplasma can survive without oxygen. Reason (R): Mycoplasma completely lacks a cell wall, making it the smallest living cell known.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 3

Logic Check

Assertion (A): Lichens are excellent indicators of air pollution. Reason (R): Lichens grow abundantly in industrially polluted areas where sulphur dioxide is present.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 4

Logic Check

Assertion (A): Diatoms are called the chief producers in the oceans. Reason (R): Diatoms are photosynthetic organisms that float passively as plankton and form the base of marine food chains.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 5

Logic Check

Assertion (A): Viruses are included in the Five Kingdom Classification under Kingdom Monera. Reason (R): Viruses are non-cellular organisms and do not possess the cellular structure required for classification in any of the five kingdoms.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 6

Logic Check

Assertion (A): Archaebacteria are found in the harshest environments on Earth. Reason (R): Archaebacteria possess a unique cell wall structure that is chemically different from the cell walls of other bacteria.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 7

Logic Check

Assertion (A): Euglena is placed in Kingdom Protista rather than Kingdom Plantae. Reason (R): Euglena has a cellulose cell wall and is exclusively photosynthetic.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 8

Logic Check

Assertion (A): Deuteromycetes are called imperfect fungi. Reason (R): Only the asexual or vegetative phases of Deuteromycetes are known; their sexual stages have not been identified.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 9

Logic Check

Assertion (A): Cyanobacteria can fix atmospheric nitrogen. Reason (R): Cyanobacteria contain specialised cells called heterocysts that provide the anaerobic microenvironment needed for nitrogen fixation.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 10

Logic Check

Assertion (A): The Two Kingdom Classification system was considered inadequate. Reason (R): The Two Kingdom system failed to distinguish between prokaryotes and eukaryotes, unicellular and multicellular organisms, and autotrophs and heterotrophs.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 11

Logic Check

Assertion (A): In Basidiomycetes, sex organs are absent. Reason (R): Plasmogamy in Basidiomycetes is brought about by fusion of two vegetative or somatic cells of different strains.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): Viroids are larger than viruses. Reason (R): Viroids consist of a free RNA molecule with no protein coat, whereas viruses have both a protein coat and nucleic acid.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 13

Logic Check

Assertion (A): Prions cause BSE in cattle and CJD in humans. Reason (R): Prions are abnormally folded proteins with no nucleic acid that induce misfolding of normal host proteins.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): All protozoans are heterotrophs. Reason (R): Protozoans are believed to be primitive relatives of animals and live as predators or parasites.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 15

Logic Check

Assertion (A): The cell walls of Kingdom Plantae are made of cellulose. Reason (R): Cellulose cell walls are the primary criterion used to distinguish Kingdom Plantae from Kingdom Fungi in the Five Kingdom Classification.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 16

Logic Check

Assertion (A): Slime mould spores are extremely resistant and can survive for many years. Reason (R): Slime mould spores possess true walls and are dispersed by air currents.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 17

Logic Check

Assertion (A): Ascomycetes produce conidia as asexual spores and ascospores as sexual spores. Reason (R): Conidia are produced endogenously in asci, while ascospores are produced exogenously on conidiophores.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 18

Logic Check

Assertion (A): Members of Kingdom Protista are primarily aquatic. Reason (R): Protista forms a link with other kingdoms dealing with plants, animals, and fungi by including unicellular eukaryotes with well-defined nuclei.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 19

Logic Check

Assertion (A): No virus contains both RNA and DNA simultaneously. Reason (R): A virus is a nucleoprotein in which the genetic material is either RNA or DNA, making the genetic material infectious.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 20

Logic Check

Assertion (A): Methanogens produce methane from the dung of ruminant animals. Reason (R): Methanogens are present in the gut of ruminant animals such as cows and buffaloes.

Reasoning Options

ByteNotes

Chapter sections

Chapter 2: Biological Classification | Assertion-Reason

Assertion (A): Bacteria are the most metabolically diverse group of organisms on Earth. Reason (R): Bacteria can be photosynthetic autotrophs, chemosynthetic autotrophs, saprophytic heterotrophs, or parasitic heterotrophs.

Assertion (A): Mycoplasma can survive without oxygen. Reason (R): Mycoplasma completely lacks a cell wall, making it the smallest living cell known.

Assertion (A): Lichens are excellent indicators of air pollution. Reason (R): Lichens grow abundantly in industrially polluted areas where sulphur dioxide is present.

Assertion (A): Diatoms are called the chief producers in the oceans. Reason (R): Diatoms are photosynthetic organisms that float passively as plankton and form the base of marine food chains.

Assertion (A): Viruses are included in the Five Kingdom Classification under Kingdom Monera. Reason (R): Viruses are non-cellular organisms and do not possess the cellular structure required for classification in any of the five kingdoms.

Assertion (A): Archaebacteria are found in the harshest environments on Earth. Reason (R): Archaebacteria possess a unique cell wall structure that is chemically different from the cell walls of other bacteria.

Assertion (A): Euglena is placed in Kingdom Protista rather than Kingdom Plantae. Reason (R): Euglena has a cellulose cell wall and is exclusively photosynthetic.

Assertion (A): Deuteromycetes are called imperfect fungi. Reason (R): Only the asexual or vegetative phases of Deuteromycetes are known; their sexual stages have not been identified.

Assertion (A): Cyanobacteria can fix atmospheric nitrogen. Reason (R): Cyanobacteria contain specialised cells called heterocysts that provide the anaerobic microenvironment needed for nitrogen fixation.

Assertion (A): The Two Kingdom Classification system was considered inadequate. Reason (R): The Two Kingdom system failed to distinguish between prokaryotes and eukaryotes, unicellular and multicellular organisms, and autotrophs and heterotrophs.

Assertion (A): In Basidiomycetes, sex organs are absent. Reason (R): Plasmogamy in Basidiomycetes is brought about by fusion of two vegetative or somatic cells of different strains.

Assertion (A): Viroids are larger than viruses. Reason (R): Viroids consist of a free RNA molecule with no protein coat, whereas viruses have both a protein coat and nucleic acid.

Assertion (A): Prions cause BSE in cattle and CJD in humans. Reason (R): Prions are abnormally folded proteins with no nucleic acid that induce misfolding of normal host proteins.

Assertion (A): All protozoans are heterotrophs. Reason (R): Protozoans are believed to be primitive relatives of animals and live as predators or parasites.

Assertion (A): The cell walls of Kingdom Plantae are made of cellulose. Reason (R): Cellulose cell walls are the primary criterion used to distinguish Kingdom Plantae from Kingdom Fungi in the Five Kingdom Classification.

Assertion (A): Slime mould spores are extremely resistant and can survive for many years. Reason (R): Slime mould spores possess true walls and are dispersed by air currents.

Assertion (A): Ascomycetes produce conidia as asexual spores and ascospores as sexual spores. Reason (R): Conidia are produced endogenously in asci, while ascospores are produced exogenously on conidiophores.

Assertion (A): Members of Kingdom Protista are primarily aquatic. Reason (R): Protista forms a link with other kingdoms dealing with plants, animals, and fungi by including unicellular eukaryotes with well-defined nuclei.

Assertion (A): No virus contains both RNA and DNA simultaneously. Reason (R): A virus is a nucleoprotein in which the genetic material is either RNA or DNA, making the genetic material infectious.

Assertion (A): Methanogens produce methane from the dung of ruminant animals. Reason (R): Methanogens are present in the gut of ruminant animals such as cows and buffaloes.

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