1. Which of the following is considered a defining feature of all living organisms without exception?
Correct Answer: C (Cellular organization and consciousness)
Non-living things can increase in mass (e.g., mountains), and sterile organisms (mules, worker bees) do not reproduce. Thus, cellular organization, metabolism, and consciousness (response to stimuli) are defining characteristics.
Non-living things can increase in mass (e.g., mountains), and sterile organisms (mules, worker bees) do not reproduce. Thus, cellular organization, metabolism, and consciousness (response to stimuli) are defining characteristics.
2. According to the rules of Binomial Nomenclature, which of the following is written correctly?
Correct Answer: B (Mangifera indica Linn.)
The genus name begins with a capital letter, the specific epithet begins with a small letter, both are italicized, and the author’s citation is written in Roman script (not italicized) at the end.
The genus name begins with a capital letter, the specific epithet begins with a small letter, both are italicized, and the author’s citation is written in Roman script (not italicized) at the end.
3. Which of the following represents the correct ascending order of taxonomic hierarchy?
Correct Answer: B (Species → Genus → Family → Order → Class → Phylum/Division → Kingdom)
The ascending hierarchy starts from the lowest, most specific taxon (Species) and moves upward to Kingdom.
The ascending hierarchy starts from the lowest, most specific taxon (Species) and moves upward to Kingdom.
4. Which of the following taxonomic categories includes all the others?
Correct Answer: C (Order)
An Order is a higher taxonomic assemblage containing one or more related Families, which in turn contain related Genera and Species.
An Order is a higher taxonomic assemblage containing one or more related Families, which in turn contain related Genera and Species.
5. The term ‘Systematics’ takes into account:
Correct Answer: C (Evolutionary (phylogenetic) relationships among organisms)
Systematics (derived from Latin *systema*) includes identification, nomenclature, classification, and specifically accounts for evolutionary relationships among organisms.
Systematics (derived from Latin *systema*) includes identification, nomenclature, classification, and specifically accounts for evolutionary relationships among organisms.
6. In taxonomic classification of plants, related orders are placed together in a:
Correct Answer: A (Class)
One or more related Orders sharing common characters are grouped together into a Class (e.g., Orders Sapindales and Polymoniales belong to Class Dicotyledonae).
One or more related Orders sharing common characters are grouped together into a Class (e.g., Orders Sapindales and Polymoniales belong to Class Dicotyledonae).
7. Two organisms belong to the same Family. They must also belong to the same:
Correct Answer: C (Order and Class)
Organisms belonging to the same lower taxon (Family) invariably share all the higher taxonomic categories above it (Order, Class, Phylum/Division, Kingdom).
Organisms belonging to the same lower taxon (Family) invariably share all the higher taxonomic categories above it (Order, Class, Phylum/Division, Kingdom).
8. In R.H. Whittaker’s Five Kingdom Classification, which criterion was NOT primarily used?
Correct Answer: C (Presence or absence of true locomotion)
The main criteria used by Whittaker (1969) were: cell structure, body organization, mode of nutrition, reproduction, and phylogenetic relationships.
The main criteria used by Whittaker (1969) were: cell structure, body organization, mode of nutrition, reproduction, and phylogenetic relationships.
9. Which group of bacteria can survive under extremely high salt conditions?
Correct Answer: B (Halophiles)
Archaebacteria living in extreme saline environments are known as halophiles. Thermoacidophiles live in hot sulfur springs, and methanogens live in marshy areas.
Archaebacteria living in extreme saline environments are known as halophiles. Thermoacidophiles live in hot sulfur springs, and methanogens live in marshy areas.
10. Specialized nitrogen-fixing cells present in cyanobacteria like Nostoc and Anabaena are called:
Correct Answer: B (Heterocysts)
Heterocysts are thick-walled, non-photosynthetic specialized cells that provide an anaerobic microenvironment for the oxygen-sensitive enzyme nitrogenase.
Heterocysts are thick-walled, non-photosynthetic specialized cells that provide an anaerobic microenvironment for the oxygen-sensitive enzyme nitrogenase.
11. Which of the following organisms completely lack a cell wall and are the smallest living cells known?
Correct Answer: A (Mycoplasma)
Mycoplasma (PPLO) are wall-less pleomorphic prokaryotes that can survive without oxygen and are resistant to antibiotics acting on cell walls (e.g., penicillin).
Mycoplasma (PPLO) are wall-less pleomorphic prokaryotes that can survive without oxygen and are resistant to antibiotics acting on cell walls (e.g., penicillin).
12. “Diatomaceous earth” is formed due to the deposition of cell walls of diatoms containing:
Correct Answer: B (Silica)
Diatom cell walls form two overlapping shells embedded with silica (frustules), making them indestructible and creating diatomaceous earth over millions of years.
Diatom cell walls form two overlapping shells embedded with silica (frustules), making them indestructible and creating diatomaceous earth over millions of years.
13. Red tides in marine waters are frequently caused by the rapid proliferation of:
Correct Answer: B (Gonyaulax)
Gonyaulax is a red dinoflagellate that multiplies rapidly, releasing toxins (saxitoxins) that can kill marine animals and tint the sea red.
Gonyaulax is a red dinoflagellate that multiplies rapidly, releasing toxins (saxitoxins) that can kill marine animals and tint the sea red.
14. Which protistan group exhibits mixotrophic nutrition (photosynthetic in sunlight and heterotrophic in the dark)?
Correct Answer: C (Euglenoids)
Euglena possesses photosynthetic pigments identical to higher plants in light, but behaves as a predator/heterotroph in darkness.
Euglena possesses photosynthetic pigments identical to higher plants in light, but behaves as a predator/heterotroph in darkness.
15. The vegetative body of slime moulds is an aggregative multinucleated mass of protoplasm called:
Correct Answer: B (Plasmodium)
Under favorable conditions, slime moulds form an aggregation called plasmodium which may grow and spread over several feet.
Under favorable conditions, slime moulds form an aggregation called plasmodium which may grow and spread over several feet.
16. The cell walls of true fungi are predominantly composed of:
Correct Answer: B (Chitin and glucans)
Fungal cell walls are characterized by chitin (a polymer of N-acetylglucosamine) and polysaccharides like glucans.
Fungal cell walls are characterized by chitin (a polymer of N-acetylglucosamine) and polysaccharides like glucans.
17. Which fungal class is commonly known as ‘Algal Fungi’ or ‘Conjugation Fungi’ and possesses coenocytic, aseptate mycelium?
Correct Answer: A (Phycomycetes)
Members of Phycomycetes (e.g., Rhizopus, Mucor, Albugo) have aseptate, multinucleated (coenocytic) mycelia.
Members of Phycomycetes (e.g., Rhizopus, Mucor, Albugo) have aseptate, multinucleated (coenocytic) mycelia.
18. Exogenously produced asexual spores called conidia are characteristic of:
Correct Answer: B (Penicillium and Aspergillus)
Ascomycetes produce asexual conidia exogenously on specialized structures called conidiophores, whereas their sexual ascospores are endogenous.
Ascomycetes produce asexual conidia exogenously on specialized structures called conidiophores, whereas their sexual ascospores are endogenous.
19. Deuteromycetes are called ‘Fungi Imperfecti’ because:
Correct Answer: B (Only their asexual or vegetative phases are known)
When sexual stages of Deuteromycetes are discovered, they are moved to Ascomycetes or Basidiomycetes (e.g., Alternaria, Colletotrichum, Trichoderma).
When sexual stages of Deuteromycetes are discovered, they are moved to Ascomycetes or Basidiomycetes (e.g., Alternaria, Colletotrichum, Trichoderma).
20. In lichens, the algal component (phycobiont) and fungal component (mycobiont) respectively perform:
Correct Answer: B (Food synthesis and water/mineral absorption with shelter)
The autotrophic phycobiont prepares food through photosynthesis, while the heterotrophic mycobiont absorbs water/nutrients and provides anchorage/protection.
The autotrophic phycobiont prepares food through photosynthesis, while the heterotrophic mycobiont absorbs water/nutrients and provides anchorage/protection.
21. Who discovered Viroids, and how do they differ from viruses?
Correct Answer: B (T.O. Diener; they consist of free RNA lacking a protein coat)
In 1971, T.O. Diener discovered viroids (causing potato spindle tuber disease), which are infectious low-molecular-weight free RNA molecules lacking a protein capsid.
In 1971, T.O. Diener discovered viroids (causing potato spindle tuber disease), which are infectious low-molecular-weight free RNA molecules lacking a protein capsid.
22. Bovine Spongiform Encephalopathy (BSE) or Mad Cow disease is caused by:
Correct Answer: B (Prions (abnormally folded proteins))
Prions are proteinaceous infectious agents with no genetic material (nucleic acids) that induce abnormal misfolding of host cellular proteins in the central nervous system.
Prions are proteinaceous infectious agents with no genetic material (nucleic acids) that induce abnormal misfolding of host cellular proteins in the central nervous system.
23. Hydrocolloids Algin and Carrageen are obtained industrially from which groups of algae respectively?
Correct Answer: A (Brown algae and Red algae)
Algin is extracted from brown algae (Phaeophyceae), and Carrageen is extracted from red algae (Rhodophyceae).
Algin is extracted from brown algae (Phaeophyceae), and Carrageen is extracted from red algae (Rhodophyceae).
24. Which major photosynthetic pigment gives brown algae (Phaeophyceae) their characteristic olive-brown color?
Correct Answer: B (Fucoxanthin)
Phaeophyceae possess chlorophyll a, c, carotenoids, and varying amounts of the xanthophyll pigment fucoxanthin.
Phaeophyceae possess chlorophyll a, c, carotenoids, and varying amounts of the xanthophyll pigment fucoxanthin.
25. Stored food material in Red Algae (Rhodophyceae) is:
Correct Answer: C (Floridean starch)
Floridean starch is structurally very similar to amylopectin and glycogen, stored in members of Rhodophyceae (e.g., Polysiphonia, Porphyra).
Floridean starch is structurally very similar to amylopectin and glycogen, stored in members of Rhodophyceae (e.g., Polysiphonia, Porphyra).
26. Which of the following algae is unicellular and exceptionally rich in proteins, used as food supplement by space travelers?
Correct Answer: A (Chlorella)
Chlorella and Spirulina are unicellular protein-rich algae frequently used as food supplements.
Chlorella and Spirulina are unicellular protein-rich algae frequently used as food supplements.
27. Why are Bryophytes commonly termed the “Amphibians of the Plant Kingdom”?
Correct Answer: B (They live on soil but require water for sexual fertilization)
Flagellated antherozoids require a film of water to swim towards the archegonium to achieve fertilization.
Flagellated antherozoids require a film of water to swim towards the archegonium to achieve fertilization.
28. In Bryophytes, the dominant independent photosynthetic phase is the:
Correct Answer: A (Free-living haploid Gametophyte)
In bryophytes, the main plant body is the haploid gametophyte. The sporophyte is physically attached and nutritionally dependent on it.
In bryophytes, the main plant body is the haploid gametophyte. The sporophyte is physically attached and nutritionally dependent on it.
29. Gemmae are specialized green, multicellular asexual buds found in:
Correct Answer: B (Marchantia)
Marchantia (liverwort) reproduces asexually via gemma cups containing haploid multicellular gemmae.
Marchantia (liverwort) reproduces asexually via gemma cups containing haploid multicellular gemmae.
30. Peat moss, which has high water-holding capacity and is used as packing material for trans-shipment of living materials, is:
Correct Answer: B (Sphagnum)
Sphagnum yields peat that has been used as fuel and possesses hygroscopic properties ideal for packaging live plants.
Sphagnum yields peat that has been used as fuel and possesses hygroscopic properties ideal for packaging live plants.
31. Which of the following plant groups were the first terrestrial plants to possess true vascular tissues (xylem and phloem)?
Correct Answer: B (Pteridophytes)
Pteridophytes (ferns and horsetails) are the earliest vascular cryptogams to evolve true tracheary elements and sieve cells.
Pteridophytes (ferns and horsetails) are the earliest vascular cryptogams to evolve true tracheary elements and sieve cells.
32. The development of the zygote into a young embryo within the female gametophyte is an important precursor to the “seed habit”, first observed in heterosporous pteridophytes like:
Correct Answer: B (Selaginella and Salvinia)
Heterospory (forming microspores and megaspores) and retention of female gametophyte on parent sporophyte in Selaginella and Salvinia marked a key evolutionary milestone toward seed habit.
Heterospory (forming microspores and megaspores) and retention of female gametophyte on parent sporophyte in Selaginella and Salvinia marked a key evolutionary milestone toward seed habit.
33. Coralloid roots associated with nitrogen-fixing cyanobacteria are found in:
Correct Answer: B (Cycas)
Cycas produces specialized apogeotropic coralloid roots containing symbiotic Anabaena/Nostoc. Pinus has mycorrhizal fungal associations.
Cycas produces specialized apogeotropic coralloid roots containing symbiotic Anabaena/Nostoc. Pinus has mycorrhizal fungal associations.
34. Gymnosperms are characterized by “naked seeds” because:
Correct Answer: B (Ovules are not enclosed inside an ovary wall)
In gymnosperms, ovules remain exposed on megasporophylls before and after fertilization; hence no fruits are formed.
In gymnosperms, ovules remain exposed on megasporophylls before and after fertilization; hence no fruits are formed.
35. The endosperm in gymnosperms is:
Correct Answer: A (Haploid (n) and formed before fertilization)
In gymnosperms, the endosperm represents the female gametophyte (n) formed prior to fertilization, unlike the triploid (3n) endosperm of angiosperms.
In gymnosperms, the endosperm represents the female gametophyte (n) formed prior to fertilization, unlike the triploid (3n) endosperm of angiosperms.
36. Water canal system (with ostia, spongocoel, and osculum) and choanocytes (collar cells) are diagnostic features of:
Correct Answer: A (Phylum Porifera)
Sponges (e.g., Sycon, Spongilla, Euspongia) possess flagellated choanocytes that line the spongocoel and canals to maintain water currents.
Sponges (e.g., Sycon, Spongilla, Euspongia) possess flagellated choanocytes that line the spongocoel and canals to maintain water currents.
37. Metagenesis (alternation of generation between sessile polyp and free-swimming medusa) is shown by:
Correct Answer: C (Obelia)
In Obelia, polyps produce medusae asexually, and medusae form polyps sexually through gamete production.
In Obelia, polyps produce medusae asexually, and medusae form polyps sexually through gamete production.
38. Bioluminescence and eight external rows of ciliated comb plates for locomotion are found in:
Correct Answer: B (Ctenophores)
Ctenophores (e.g., Pleurobrachia, Ctenoplana), commonly known as comb jellies, exhibit distinctive ciliated comb plates and bioluminescence.
Ctenophores (e.g., Pleurobrachia, Ctenoplana), commonly known as comb jellies, exhibit distinctive ciliated comb plates and bioluminescence.
39. Flame cells (Protonephridia) function primarily for osmoregulation and excretion in:
Correct Answer: A (Platyhelminthes (Flatworms))
Flatworms such as Planaria, Taenia, and Fasciola use specialized flame cells for osmoregulation and waste removal.
Flatworms such as Planaria, Taenia, and Fasciola use specialized flame cells for osmoregulation and waste removal.
40. Which of the following phyla contains organisms that are pseudocoelomate, triploblastic, and unsegmented?
Correct Answer: B (Aschelminthes (Nematoda))
Roundworms (e.g., Ascaris, Wuchereria, Ancylostoma) possess a body cavity derived from the blastocoel (pseudocoelom) rather than mesoderm.
Roundworms (e.g., Ascaris, Wuchereria, Ancylostoma) possess a body cavity derived from the blastocoel (pseudocoelom) rather than mesoderm.
41. Metameric segmentation and parapodia for swimming are characteristic of:
Correct Answer: A (Nereis (Phylum Annelida))
Annelids exhibit true metamerism; aquatic annelids like Nereis possess lateral appendages called parapodia for locomotion.
Annelids exhibit true metamerism; aquatic annelids like Nereis possess lateral appendages called parapodia for locomotion.
42. Malpighian tubules are excretory structures in which largest phylum of the animal kingdom?
Correct Answer: B (Arthropoda)
Insects and many other terrestrial arthropods utilize Malpighian tubules to excrete nitrogenous waste as uric acid.
Insects and many other terrestrial arthropods utilize Malpighian tubules to excrete nitrogenous waste as uric acid.
43. A file-like rasping organ used for feeding called the “Radula” is present in:
Correct Answer: B (Molluscs)
The mouth of molluscs (e.g., Pila, Sepia, Loligo) contains a chitinous rasping organ called the radula.
The mouth of molluscs (e.g., Pila, Sepia, Loligo) contains a chitinous rasping organ called the radula.
44. Water vascular system (ambulacral system) assisting in locomotion, capture of food, and respiration is unique to:
Correct Answer: B (Echinodermata)
Adult echinoderms (e.g., Asterias, Echinus, Cucumaria) have radial symmetry and a mesodermally derived water vascular system with tube feet.
Adult echinoderms (e.g., Asterias, Echinus, Cucumaria) have radial symmetry and a mesodermally derived water vascular system with tube feet.
45. Which of the following is NOT one of the three fundamental hallmark characteristics of Phylum Chordata?
Correct Answer: D (Ventral solid nerve cord)
Non-chordates possess a double, ventral, solid nerve cord. Chordates are distinguished by a single, dorsal, hollow nerve cord, notochord, and post-anal tail.
Non-chordates possess a double, ventral, solid nerve cord. Chordates are distinguished by a single, dorsal, hollow nerve cord, notochord, and post-anal tail.
46. In Urochordata (Tunicata), the notochord is present only in:
Correct Answer: A (The larval tail)
In urochordates (e.g., Ascidia, Salpa, Doliolum), the notochord is restricted to the larval tail and lost in retrogressive metamorphosis. In cephalochordates (Branchiostoma), it extends from head to tail throughout life.
In urochordates (e.g., Ascidia, Salpa, Doliolum), the notochord is restricted to the larval tail and lost in retrogressive metamorphosis. In cephalochordates (Branchiostoma), it extends from head to tail throughout life.
47. Jawless vertebrates (Agnatha) with a circular sucking mouth and cartilaginous cranium belong to Class:
Correct Answer: A (Cyclostomata)
Cyclostomes (e.g., Petromyzon – Lamprey, and Myxine – Hagfish) are ectoparasites on fishes possessing a circular sucking and suctorial mouth devoid of jaws.
Cyclostomes (e.g., Petromyzon – Lamprey, and Myxine – Hagfish) are ectoparasites on fishes possessing a circular sucking and suctorial mouth devoid of jaws.
48. Cartilaginous fishes (Chondrichthyes) differ from bony fishes (Osteichthyes) because Chondrichthyes have:
Correct Answer: A (Placoid scales and absence of an operculum (gill cover))
Chondrichthyes (e.g., Scoliodon, Pristis) have tooth-like placoid scales, lack an operculum, lack swim bladders (must swim continuously to avoid sinking), and have ventral mouths.
Chondrichthyes (e.g., Scoliodon, Pristis) have tooth-like placoid scales, lack an operculum, lack swim bladders (must swim continuously to avoid sinking), and have ventral mouths.
49. Pneumatic (air cavity filled) bones, absence of urinary bladder, and presence of crop and gizzard are characteristic adaptations in:
Correct Answer: B (Class Aves)
Birds (e.g., Corvus, Columba, Neophron) possess hollow pneumatic bones to reduce weight for flight, along with an alimentary canal equipped with a crop and gizzard.
Birds (e.g., Corvus, Columba, Neophron) possess hollow pneumatic bones to reduce weight for flight, along with an alimentary canal equipped with a crop and gizzard.
50. Which of the following is an oviparous (egg-laying) mammal?
Correct Answer: A (Ornithorhynchus (Platypus))
Ornithorhynchus (Duck-billed platypus) is a prototherian oviparous mammal, while almost all other mammals are viviparous.
Ornithorhynchus (Duck-billed platypus) is a prototherian oviparous mammal, while almost all other mammals are viviparous.