1. Who proposed the five-kingdom classification?
A) Aristotle
B) Linnaeus
C) Whittaker
D) Haeckel
Answer: C
Explanation: R.H. Whittaker (1969) proposed five kingdoms: Monera, Protista, Fungi, Plantae, Animalia.
2. Two kingdom classification was given by:
A) Darwin
B) Aristotle
C) Linnaeus
D) Whittaker
Answer: C
Explanation: Carolus Linnaeus classified living organisms into Plantae and Animalia.
3. Which of the following organisms are prokaryotic?
A) Fungi
B) Bacteria
C) Protozoa
D) Algae
Answer: B
Explanation: Prokaryotes lack a true nucleus; bacteria are the main group.
4. In Whittaker’s system, unicellular eukaryotes are placed under:
A) Protista
B) Monera
C) Fungi
D) Plantae
Answer: A
Explanation: Protista includes unicellular eukaryotes like Amoeba, Paramecium.
5. Chitinous cell walls are found in:
A) Plants
B) Fungi
C) Bacteria
D) Algae
Answer: B
Explanation: Fungal cell walls are made of chitin, not cellulose.
6. Which of the following are autotrophic prokaryotes?
A) Blue-green algae
B) Fungi
C) Protozoa
D) Algae
Answer: A
Explanation: Cyanobacteria (blue-green algae) are photosynthetic prokaryotes.
7. Binomial nomenclature was introduced by:
A) Darwin
B) Linnaeus
C) Whittaker
D) Aristotle
Answer: B
Explanation: Linnaeus introduced binomial nomenclature — genus and species names.
8. Five kingdom classification is based on:
A) Nutrition, cell structure, body organization
B) Habitat and size
C) Color and shape
D) Complexity of organs
Answer: A
Explanation: Whittaker considered cell type, structure, nutrition, reproduction.
9. Which group includes extremophiles?
A) Protista
B) Archaebacteria
C) Fungi
D) Plantae
Answer: B
Explanation: Archaebacteria live in extreme conditions (hot springs, salty lakes).
10. Kingdom Monera includes:
A) Fungi
B) Protozoa
C) Bacteria
D) Algae
Answer: C
Explanation: Monera = prokaryotes (bacteria, archaea, cyanobacteria).
11. Viruses are placed in classification as:
A) Prokaryotes
B) Eukaryotes
C) Not truly living organisms
D) Protists
Answer: C
Explanation: Viruses are acellular, placed outside traditional classification.
12. The term “taxonomy” was coined by:
A) Linnaeus
B) A.P. de Candolle
C) Darwin
D) Whittaker
Answer: B
Explanation: Candolle (1813) coined taxonomy — science of classification.
13. Which of the following is a heterotrophic organism?
A) Algae
B) Bacteria (some)
C) Cyanobacteria
D) Ferns
Answer: B
Explanation: Some bacteria are saprophytic, parasitic → heterotrophs.
14. Mycoplasma differ from other prokaryotes in:
A) Having cell wall
B) Absence of cell wall
C) Having nucleus
D) Photosynthesis
Answer: B
Explanation: Mycoplasma are wall-less prokaryotes, smallest free-living cells.
15. Binomial nomenclature uses:
A) Latin words only
B) English + Latin
C) Any language
D) Greek words only
Answer: A
Explanation: Latin is universal, not changing with time.
16. Which is the smallest unit of classification?
A) Genus
B) Family
C) Species
D) Order
Answer: C
Explanation: Species is the basic unit of taxonomy.
17. The three-domain classification was given by:
A) Darwin
B) Carl Woese
C) Whittaker
D) Linnaeus
Answer: B
Explanation: Woese (1990) → three domains: Archaea, Bacteria, Eukarya.
18. Protists differ from Monerans in having:
A) Nucleus
B) Cell wall
C) Ribosomes
D) DNA
Answer: A
Explanation: Protists are eukaryotic; Monerans prokaryotic.
19. Which of the following are considered “acellular”?
A) Fungi
B) Viruses
C) Bacteria
D) Algae
Answer: B
Explanation: Viruses lack cell structure; only nucleic acid + protein coat.
20. Which organism shows both autotrophy and heterotrophy?
A) Euglena
B) Amoeba
C) Fungi
D) Plasmodium
Answer: A
Explanation: Euglena is mixotrophic → photosynthetic + saprophytic.
21. Which kingdom includes slime molds?
A) Protista
B) Fungi
C) Plantae
D) Monera
Answer: A
Explanation: Slime molds → fungus-like protists, saprophytic.
22. Diatoms are included in:
A) Protista
B) Plantae
C) Monera
D) Fungi
Answer: A
Explanation: Diatoms are unicellular algae (Protista).
23. Which are prokaryotic photoautotrophs?
A) Algae
B) Cyanobacteria
C) Protozoa
D) Slime molds
Answer: B
Explanation: Cyanobacteria → oxygenic photosynthetic prokaryotes.
24. Genetic material in prokaryotes is:
A) Linear DNA
B) Circular DNA
C) Double helix in nucleus
D) RNA only
Answer: B
Explanation: Bacterial DNA is circular, not enclosed by nucleus.
25. Which of the following lacks histone proteins?
A) Archaea
B) Bacteria
C) Eukaryotes
D) Protists
Answer: B
Explanation: Bacteria lack histones; Archaea and Eukarya have histoes.
26. Bacteria reproduce mainly by:
A) Binary fission
B) Conjugation
C) Spore formation
D) Budding
Answer: A
Explanation: Bacteria multiply rapidly by asexual reproduction → binary fission. Conjugation and spore formation are rare.
27. The bacterial cell wall is mainly composed of:
A) Cellulose
B) Chitin
C) Peptidoglycan
D) Lignin
Answer: C
Explanation: Peptidoglycan (murein) provides rigidity to bacterial walls.
28. Archaebacteria differ from eubacteria in:
A) Absence of DNA
B) Different cell wall composition
C) Presence of mitochondria
D) Having peptidoglycan
Answer: B
Explanation: Archaebacteria lack peptidoglycan, have unique polysaccharides & proteins.
29. Which of the following bacteria are used in sewage treatment?
A) Methanogens
B) Cyanobacteria
C) Thermoacidophiles
D) Halophiles
Answer: A
Explanation: Methanogens (Archaea) prouce methane and help in biogas and sewage treatment.
30. Which are the smallest known free-living organisms?
A) Viruses
B) Mycoplasma
C) Cyanobacteria
D) Archaebacteria
Answer: B
Explanation: Mycoplasma are wall-less bacteria, smallest living organisms (~0.1 μm).
31. Nitrogen-fixing bacteria found in root nodules of legumes are:
A) Azotobacter
B) Rhizobium
C) Clostridium
D) Nitrobacter
Answer: B
Explanation: Symbiotic nitrogen fixer in leguminous root nodules = Rhizobium.
32. Which bacteria convert milk into curd?
A) Lactobacillus
B) Rhizobium
C) Nitrosomonas
D) Pseudomonas
Answer: A
Explanation: Lactobacillus ferments lactose into lactic acid → curd formation.
33. Cyanobacteria are also called:
A) Blue-green algae
B) Brown algae
C) Red algae
D) Golden algae
Answer: A
Explanation: Cyanobacteria are photosynthetic prokaryotes, called blue-green algae.
34. Photosynthetic pigments in cyanobacteria are:
A) Chlorophyll a and b
B) Chlorophyll a and phycobilins
C) Chlorophyll b and carotenoids
D) Chlorophyll c and xanthophyll
Answer: B
Explanation: Cyanobacteria have chlorophyll a and phycobiliproteins (phycocyanin, phycoerythrin).
35. Which protist causes malaria?
A) Amoeba
B) Paramecium
C) Plasmodium
D) Trypanosoma
Answer: C
Explanation: Plasmodium (protozoan) causes malaria, transmitted by female Anopheles mosquito.
36. Trypanosoma is transmitted by:
A) Sand fly
B) Housefly
C) Tsetse fly
D) Mosquito
Answer: C
Explanation: Trypanosoma causes African sleeping sickness, spread by tsetse fly.
37. Which protist has both plant-like and animal-like features?
A) Amoeba
B) Paramecium
C) Euglena
D) Plasmodium
Answer: C
Explanation: Euglena is mixotrophic → photosynthetic in light, heterotrophic in dark.
38. Diatoms are called:
A) Golden algae
B) Brown algae
C) Dinoflagellates
D) Green algae
Answer: A
Explanation: Diatoms belong to Chrysophyta (golden algae), cell walls impregnated with silica.
39. The two flagella of Euglena are:
A) Equal
B) Unequal
C) Absent
D) Both very long
Answer: B
Explanation: Euglena has one long flagellum and one short → unequal flagella.
40. Which protists have stiff cellulose plates in their cell wall?
A) Dinoflagellates
B) Diatoms
C) Euglenoids
D) Slime molds
Answer: A
Explanation: Dinoflagellates (e.g., Gonyaulax) have cellulose plates in theca.
41. Red tide is caused by:
A) Cyanobacteria
B) Dinoflagellates
C) Euglena
D) Slime molds
Answer: B
Explanation: Gonyaulax (dinoflagellate) → rapid growth → red tide, toxic to fishes.
42. Paramecium moves with the help of:
A) Flagella
B) Cilia
C) Pseudopodia
D) None
Answer: B
Explanation: Paramecium uses cilia for locomotion and feeding.
43. Amoeba captures food by:
A) Flagella
B) Pseudopodia
C) Cilia
D) Tentacles
Answer: B
Explanation: Amoeba → phagocytosis by pseudopodia (false feet).
44. The slimy mass of multinucleated protoplasm in slime molds is called:
A) Plasmodium (not malaria parasite)
B) Mycelium
C) Thallus
D) Zygospore
Answer: A
Explanation: Slime molds form a multinucleated plasmodium (vegetative stage).
45. Which protists are called “cosmic scavengers”?
A) Euglena
B) Amoeba
C) Slime molds
D) Diatoms
Answer: C
Explanation: Slime molds feed on decaying organic matter, act as natural scavengers.
46. Which protist is known as “sea sparkle”?
A) Euglena
B) Amoeba
C) Noctiluca
D) Paramecium
Answer: C
Explanation: Dinoflagellate Noctiluca → bioluminescence → sea sparkle.
47. Which protist has two types of nuclei (macro and micro)?
A) Amoeba
B) Paramecium
C) Euglena
D) Plasmodium
Answer: B
Explanation: Paramecium has a macronucleus (metabolism) and micronucleus (reproduction).
48. The cell wall of diatoms is made of:
A) Cellulose
B) Pectin
C) Silica
D) Chitin
Answer: C
Explanation: Diatoms have siliceous walls (frustules) → indestructible.
49. The reserve food material in diatoms is:
A) Glycogen
B) Starch
C) Oil droplets
D) Sucrose
Answer: C
Explanation: Diatoms store food as oils and polysaccharide called leucosin.
50. Protists differ from monerans mainly in:
A) Cell wall
B) Nuclear organization
C) Mode of nutrition
D) Habitat
Answer: B
Explanation: Protists are eukaryotes with nucleus and organelles; monerans are prokaryotes.
51. Which of the following fungi produce motile spores?
A) Ascomycota
B) Basidiomycota
C) Chytridiomycota
D) Zygomycota
Answer: C
Explanation: Primitive chytrids produce flagellated zoospores.
52. Which is known as “imperfect fungi”?
A) Zygomycota
B) Basidiomycota
C) Ascomycota
D) Deuteromycota
Answer: D
Explanation: Deuteromycota = fungi imperfecti, as their sexual stage is absent/unknown.
53. Fungal cell walls are made up of:
A) Cellulose
B) Chitin
C) Peptidoglycan
D) Silica
Answer: B
Explanation: Unlike plants (cellulose), fungi have chitinous walls.
54. Yeast is classified under:
A) Ascomycota
B) Basidiomycota
C) Zygomycota
D) Chytridiomycota
Answer: A
Explanation: Yeast reproduces by budding; belongs to sac fungi (Ascomycota).
55. Edible mushrooms belong to:
A) Zygomycota
B) Basidiomycota
C) Ascomycota
D) Chytridiomycota
Answer: B
Explanation: Mushrooms are basidiomycetes (club fungi).
56. Penicillium is important because it produces:
A) Alcohol
B) Penicillin
C) Citric acid
D) Lactic acid
Answer: B
Explanation: Penicillium notatum produces penicillin (first antibiotic).
57. Which of the following are non-vascular plants?
A) Bryophytes
B) Pteridophytes
C) Gymnosperms
D) Angiosperms
Answer: A
Explanation: Bryophytes lack vascular tissues (xylem and phloem).
58. Bryophytes are called amphibians of plant kingdom because:
A) They grow in water only
B) They grow on land but need water for fertilization
C) They are aquatic only
D) They produce both seeds and spores
Answer: B
Explanation: Bryophyte sperm (antherozoids) need water to reach egg.
59. Moss plant body is:
A) Sporophytic
B) Gametophytic
C) Both equally
D) None
Answer: B
Explanation: Dominant phase in bryophytes is haploid gametophyte.
60. Which plant group is the first vascular plant group?
A) Bryophytes
B) Pteridophytes
C) Gymnosperms
D) Angiosperms
Answer: B
Explanation: Pteridophytes → first land plants with xylem and phloem.
61. Gymnosperms differ from angiosperms in having:
A) Seeds not enclosed in fruit
B) Flowers
C) Double fertilization
D) Endosperm
Answer: A
Explanation: Gymnosperms = naked seeds; angiosperms = seeds inside fruit.
62. Double fertilization is a characteristic of:
A) Bryophytes
B) Gymnosperms
C) Angiosperms
D) Pteridophytes
Answer: C
Explanation: In angiosperms, one sperm fuses with egg (zygote) and another with polar nuclei (endosperm).
63. Which algae are used as food in Japan?
A) Spirogyra
B) Laminaria and Porphyra
C) Ulothrix
D) Volvox
Answer: B
Explanation: Brown (Laminaria) and red (Porphyra) algae used as sea food.
64. Agar is obtained from:
A) Red algae
B) Brown algae
C) Green algae
D) Cyanobacteria
Answer: A
Explanation: Red algae like Gelidium and Gracilaria → agar source.
65. Green algae store food as:
A) Glycogen
B) Starch
C) Oil
D) Protein
Answer: B
Explanation: Chlorophyceae (green algae) store starch.
66. Brown algae store food as:
A) Starch
B) Mannitol and laminarin
C) Oil
D) Protein
Answer: B
Explanation: Phaeophyceae (brown algae) store food as complex carbs mannitol & laminarin.
67. Red algae store food as:
A) Floridean starch
B) Laminarin
C) Glycogen
D) Oil
Answer: A
Explanation: Rhodophyceae (red algae) store floridean starch.
68. Which kingdom includes heterotrophic, multicellular, eukaryotic organisms without cell wall?
A) Plantae
B) Fungi
C) Animalia
D) Protista
Answer: C
Explanation: Animals lack cell walls, are heterotrophic and multicellular.
69. Sponges belong to phylum:
A) Coelenterata
B) Porifera
C) Mollusca
D) Echinodermata
Answer: B
Explanation: Sponges are simplest multicellular animals → Porifera.
70. Cnidoblasts (stinging cells) are found in:
A) Porifera
B) Cnidaria
C) Platyhelminthes
D) Annelida
Answer: B
Explanation: Jellyfish, Hydra have cnidoblasts for defense & capturing prey.
71. Which is the first phylum to show bilateral symmetry?
A) Porifera
B) Cnidaria
C) Platyhelminthes
D) Annelida
Answer: C
Explanation: Flatworms → first bilaterally symmetrical animals.
72. Animals with true coelom lined by mesoderm are called:
A) Acoelomates
B) Pseudocoelomates
C) Coelomates (eucoelomates)
D) None
Answer: C
Explanation: True coelomates include annelids, mollusks, arthropods, chordates.
73. Exoskeleton of arthropods is made up of:
A) Lignin
B) Cellulose
C) Chitin
D) Keratin
Answer: C
Explanation: Arthropods (insects, crustaceans) → chitinous exoskeleton.
74. Which animal group has notochord at some stage?
A) Mollusca
B) Annelida
C) Chordata
D) Arthropoda
Answer: C
Explanation: Notochord present in chordates (at least in embryonic stage).
75. Mammals differ from other vertebrates in having:
A) Scales
B) Mammary glands
C) Gills
D) Cold blood
Answer: B
Explanation: Mammals nourish young with milk secreted by mammary glands.
76. Viruses are considered living because:
A) They have cell walls
B) They can respire independently
C) They reproduce inside a host cell
D) They are multicellular
Answer: C
Explanation: Viruses show living characters (reproduction, mutation) only inside host cells.
77. The first discovered virus was:
A) HIV
B) TMV (Tobacco Mosaic Virus)
C) Influenza virus
D) Polio virus
Answer: B
Explanation: Discovered by Dmitri Ivanovsky in 1892; later studied by Beijerinck.
78. The genetic material of HIV is:
A) dsDNA
B) ssRNA
C) dsRNA
D) ssDNA
Answer: B
Explanation: HIV is a retrovirus with single-stranded RNA and reverse transcriptase enzyme.
79. Which infectious agent consists only of naked RNA?
A) Prions
B) Viruses
C) Viroids
D) Bacteriophages
Answer: C
Explanation: Viroids are small, circular RNA molecules without protein coat.
80. Prions are:
A) Proteinaceous infectious agents
B) DNA viruses
C) RNA viruses
D) Fungal spores
Answer: A
Explanation: Prions are abnormal proteins causing diseases like Mad Cow Disease.
81. Which disease is caused by prions?
A) Creutzfeldt-Jakob disease
B) Tuberculosis
C) Polio
D) Malaria
Answer: A
Explanation: Prions cause neurodegenerative diseases in humans and animals.
82. Bacteriophages are viruses that infect:
A) Fungi
B) Plants
C) Animals
D) Bacteria
Answer: D
Explanation: Bacteriophages (phages) are viruses that attack bacterial cells.
83. Which cycle of bacteriophage results in lysis of host cell?
A) Lysogenic cycle
B) Lytic cycle
C) Retroviral cycle
D) Dormant cycle
Answer: B
Explanation: In the lytic cycle, host cell bursts releasing new viruses.
84. Which cycle integrates viral DNA into host DNA?
A) Lytic cycle
B) Lysogenic cycle
C) Sporulation
D) Binary fission
Answer: B
Explanation: In lysogeny, viral DNA integrates into host genome and multiplies silently.
85. Who crystallized the Tobacco Mosaic Virus (TMV)?
A) Louis Pasteur
B) Stanley
C) Ivanovsky
D) Koch
Answer: B
Explanation: W.M. Stanley (1935) crystallized TMV, showing it behaves like chemical.
86. The protein coat of virus is called:
A) Envelope
B) Capsid
C) Capsomere
D) Virion
Answer: B
Explanation: Capsid surrounds viral genome; made of capsomeres.
87. Lichens are a symbiotic association of:
A) Fungus and bacteria
B) Algae and fungus
C) Plant and animal
D) Bacteria and protozoa
Answer: B
Explanation: Algae provide food (photosynthesis); fungus provides water and shelter.
88. Which of the following is a pioneer colonizer of bare rocks?
A) Moss
B) Fern
C) Lichen
D) Grass
Answer: C
Explanation: Lichens are first to grow on bare rocks, starting ecological succession.
89. In lichens, fungal partner is called:
A) Mycobiont
B) Phycobiont
C) Saprophyte
D) Parasite
Answer: A
Explanation: Fungus = mycobiont (gives structure), Alga = phycobiont (photosynthesis).
90. Lichens are indicators of:
A) Soil fertility
B) Water pollution
C) Air pollution
D) Radioactive pollution
Answer: C
Explanation: Lichens are highly sensitive to SO₂ → indicators of air quality.
91. Which group is considered a link between living and non-living?
A) Protozoa
B) Viruses
C) Mycoplasma
D) Cyanobacteria
Answer: B
Explanation: Viruses are inert outside host (non-living), active inside host (living).
92. Which statement about viruses is false?
A) They contain either DNA or RNA
B) They can multiply outside host cells
C) They are obligate parasites
D) They are acellular
Answer: B
Explanation: Viruses cannot reproduce outside host → obligate parasites.
93. Which of the following contain both DNA and RNA?
A) Viruses
B) Prions
C) Viroids
D) None
Answer: D
Explanation: Viruses contain either DNA or RNA, never both.
94. A virus without its protein coat is called:
A) Prion
B) Virion
C) Naked virus
D) Viroid
Answer: D
Explanation: Viroids are naked RNA molecules without protein coat.
95. Infective protein particles are called:
A) Viroids
B) Prions
C) Virions
D) Capsids
Answer: B
Explanation: Prions = infectious proteins → no nucleic acids.
96. Which of the following is a DNA virus?
A) Adenovirus
B) TMV
C) HIV
D) Influenza virus
Answer: A
Explanation: Adenoviruses are double-stranded DNA viruses causing respiratory diseases.
97. Which of the following is an RNA virus?
A) HIV
B) Hepatitis B virus
C) Adenovirus
D) Herpes virus
Answer: A
Explanation: Retrovirus HIV carries RNA as genetic material.
98. Which organism shows symbiosis similar to lichens?
A) Mycorrhiza
B) Amoeba
C) Plasmodium
D) Euglena
Answer: A
Explanation: Mycorrhiza = association between fungi and roots of higher plants.
99. Which is called “living fossil” among prokaryotes?
A) Archaebacteria
B) Cyanobacteria
C) Mycoplasma
D) Thermoacidophiles
Answer: B
Explanation: Cyanobacteria (blue-green algae) are ancient, still surviving since Precambrian times.
100. Which of the following is true about classification?
A) Taxonomy and classification are unrelated
B) Binomial nomenclature uses English names
C) Classification helps in identification of organisms
D) Classification is not needed in biology
Answer: C
Explanation: Classification organizes organisms systematically for easy identification and study.