Biological Classification – Introduction: NEET MCQs with Answers

Explanation: Pseudopodia occur in amoeboid protozoans (e.g., Amoeba), not in sporozoans; sporozoans such as Plasmodium have no locomotory structures. Fungi and plants have cell walls, mushrooms are basidiomycetes, and Monera lack mitochondria.

Explanation: Large central vacuoles are characteristic of plant cells; animal cells have small vacuoles. Protists are eukaryotes, methanogens are prokaryotic archaebacteria, and gas vacuoles occur in photosynthetic (blue-green/green) bacteria.

Explanation: Eubacteria are the 'true bacteria'; it is the Archaebacteria that differ from them, so calling eubacteria 'false bacteria' is wrong. Cyanobacteria are blue-green algae, chrysophytes (golden algae) include desmids, and phycomycetes are commonly called algal fungi.

Explanation: Pseudopodia are the locomotory and feeding structures of AMOEBOID protozoans (e.g. Amoeba, Entamoeba). Sporozoans possess an infectious spore-like stage and move by gliding, not by pseudopodia.

Explanation: Eubacteria are the TRUE bacteria, not false bacteria. Cyanobacteria are indeed blue-green algae, NCERT refers to the golden algae of Chrysophytes as desmids, and Phycomycetes are called algal fungi because of their aquatic habitat and coenocytic mycelium.

Explanation: Monera are prokaryotes and therefore lack a nuclear membrane; their genetic material lies free in the cytoplasm as a nucleoid. The other three statements are correct.

Explanation: Whittaker's criteria were complexity of cell structure, complexity of body organisation, mode of nutrition, mode of reproduction and phylogenetic relationships. Mere presence or absence of a well defined nucleus alone was not used as a criterion — that is a feature of cell structure but not one of the stated bases.

Explanation: Among the criteria used by Whittaker, mode of nutrition (autotrophic, heterotrophic — saprophytic, parasitic or holozoic) is the main basis on which Plantae, Fungi and Animalia are separated from one another. Cell wall structure and asexual reproduction were not used as the primary basis of division.

Explanation: Chlamydomonas and Chlorella are unicellular eukaryotic organisms, and the five kingdom system places all unicellular eukaryotes in Protista. Thus these two green algae were brought together with Amoeba in kingdom Protista, even though earlier classifications had placed them among plants.

Explanation: Whittaker's five kingdom system used cell structure, thallus (body) organisation, mode of nutrition, mode of reproduction and phylogenetic relationships as its criteria. Presence or absence of a well-defined nucleus by itself was not listed as a separate basis — it is included within the broader criterion of cell structure.

Explanation: Monera is the kingdom of unicellular organisms with prokaryotic cell organisation — they lack a nuclear membrane and all other membrane-bound organelles, possessing only a nucleoid. The other three statements are correct: animal cells have no cell wall, Protista include both photosynthetic (Euglena, dinoflagellates) and heterotrophic (Amoeba, Paramecium) forms, and fungi such as mushrooms, morels and truffles are edible.

Explanation: Plasmodium and Trypanosoma are protozoan parasites while Cuscuta is a parasitic flowering plant, so it is the genuine exception. UAA, UAG and UGA are all stop codons, typhoid, pneumonia and diphtheria are all bacterial, and kangaroo, koala and wombat are all marsupials, so the exceptions named in those sets are wrong.

Explanation: NCERT restricts Kingdom Protista to chrysophytes, dinoflagellates, euglenoids, slime moulds and protozoans, and treats all algae — including the unicellular green algae Chlamydomonas and Chlorella — as members of Chlorophyceae within Kingdom Plantae. Both are eukaryotic and possess chlorophyll a and b with starch as the reserve food, which is the plant pattern. 'Algae' is not a kingdom in the five-kingdom scheme at all, and Monera is excluded because these organisms are eukaryotic.

Explanation: Decomposition of dead organic matter is carried out chiefly by saprotrophic bacteria (Monera) and fungi, both of which secrete extracellular digestive enzymes and then absorb the simplified soluble products. This absorptive saprotrophic mode is what makes them the principal decomposers of the biosphere and returns mineral nutrients to the soil. Members of Plantae are autotrophic and animals are ingestive heterotrophs, so neither functions as a true decomposer.

Explanation: Whittaker (1969) used three main criteria — complexity of cell structure (prokaryotic versus eukaryotic), complexity of body organisation (unicellular versus multicellular) and mode of nutrition — but it is the mode of nutrition that principally separates the three multicellular kingdoms from one another: Plantae are photosynthetic autotrophs, Fungi are absorptive heterotrophs and Animalia are ingestive heterotrophs. Cell wall structure and reproduction were used only as supporting characters, and nuclear structure alone would separate Monera from the rest but not the remaining four kingdoms.