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1. The five kingdom system of classification was proposed by
A. R.H. Whittaker
B. Carolus Linnaeus
C. Charles Darwin
D. Aristotle
Answer: A. R.H. Whittaker
Explanation: R.H. Whittaker proposed the five kingdom classification (Monera, Protista, Fungi, Plantae, Animalia) in 1969, based on cell structure, mode of nutrition, and body organisation.
2. The five kingdom classification is based on characteristics like
A. Cell structure, body organisation, mode of nutrition, and phylogenetic relationships
B. Only the size of the organism
C. Only the color of the organism
D. Only the geographical location where the organism is found
Answer: A. Cell structure, body organisation, mode of nutrition, and phylogenetic relationships
Explanation: Whittaker's five kingdom system considers cell structure (prokaryotic/eukaryotic), body organisation, mode of nutrition, reproduction, and evolutionary relationships among organisms.
10. Kingdom Monera includes organisms that are
A. Prokaryotic
B. Eukaryotic
C. Multicellular only
D. Photosynthetic only
Answer: A. Prokaryotic
Explanation: Kingdom Monera comprises all prokaryotic organisms, including bacteria, which lack a well-defined nucleus and membrane-bound organelles.
3. Which of the following is a characteristic feature of bacteria (Monera)?
A. Absence of a nuclear membrane, so DNA lies free in the cytoplasm
B. Presence of a well-defined nucleus with a nuclear membrane
C. Presence of membrane-bound organelles like mitochondria
D. Multicellular body organisation exclusively
Answer: A. Absence of a nuclear membrane, so DNA lies free in the cytoplasm
Explanation: Bacteria are prokaryotes lacking a well-defined nuclear membrane and membrane-bound organelles; their genetic material lies free in the cytoplasm as a nucleoid.
4. Archaebacteria are known to differ from other bacteria (eubacteria) mainly due to differences in
A. Cell wall composition, allowing them to survive extreme conditions
B. Presence of a well-defined nucleus
C. Multicellularity
D. Being exclusively photosynthetic
Answer: A. Cell wall composition, allowing them to survive extreme conditions
Explanation: Archaebacteria differ from eubacteria in their cell wall composition, which allows them to survive extreme environments such as high salt (halophiles), hot springs (thermoacidophiles), and marshy areas (methanogens).
5. Cyanobacteria are also known as
A. Blue-green algae
B. Red algae
C. Brown algae
D. Green fungi
Answer: A. Blue-green algae
Explanation: Cyanobacteria, also called blue-green algae, are photosynthetic prokaryotes with chlorophyll and often possess a mucilaginous sheath around their cells.
6. Nitrogen-fixing bacteria that live symbiotically in the root nodules of leguminous plants belong to the genus
A. Rhizobium
B. Nostoc
C. Escherichia
D. Mycobacterium
Answer: A. Rhizobium
Explanation: Rhizobium bacteria form a symbiotic association with the roots of leguminous plants, fixing atmospheric nitrogen in root nodules, benefiting both the bacteria and the plant.
7. Kingdom Protista mainly includes
A. Unicellular eukaryotic organisms
B. Multicellular prokaryotic organisms
C. Unicellular prokaryotic organisms
D. All multicellular animals
Answer: A. Unicellular eukaryotic organisms
Explanation: Kingdom Protista consists mainly of single-celled eukaryotic organisms that form a link between Monera, Plantae, Animalia, and Fungi, such as Amoeba and diatoms.
8. Chrysophytes, dinoflagellates, and euglenoids are all examples of organisms belonging to Kingdom
A. Protista
B. Monera
C. Fungi
D. Plantae
Answer: A. Protista
Explanation: Chrysophytes (like diatoms), dinoflagellates, and euglenoids are all unicellular eukaryotic organisms classified under Kingdom Protista.
9. Euglena is classified as a protist that shows characteristics of both a plant and an animal because it
A. Has chlorophyll for photosynthesis but lacks a cell wall, and can also feed like an animal in absence of light
B. Is always photosynthetic and never feeds like an animal
C. Has a rigid cell wall like plants and no flagellum
D. Reproduces sexually only, like animals
Answer: A. Has chlorophyll for photosynthesis but lacks a cell wall, and can also feed like an animal in absence of light
Explanation: Euglena has chloroplasts for photosynthesis (plant-like) in the presence of sunlight, but lacks a cell wall and switches to heterotrophic nutrition (animal-like) when light is unavailable.
11. Kingdom Fungi consists of organisms that are mainly
A. Heterotrophic and absorb nutrients through saprophytic or parasitic modes
B. Autotrophic with chlorophyll for photosynthesis
C. Prokaryotic
D. Exclusively unicellular
Answer: A. Heterotrophic and absorb nutrients through saprophytic or parasitic modes
Explanation: Fungi lack chlorophyll and are heterotrophic, obtaining nutrition by absorbing organic matter through saprophytic (decaying matter) or parasitic (living host) modes.
12. The cell wall of fungi is primarily made up of
A. Chitin
B. Cellulose
C. Peptidoglycan
D. Lignin
Answer: A. Chitin
Explanation: The cell walls of fungi are composed of chitin (a polysaccharide) and other complex sugars, differentiating them from plant cell walls, which are made of cellulose.
13. The vegetative body of most fungi is made up of thread-like structures called
A. Hyphae, collectively called mycelium
B. Roots
C. Nodes
D. Rhizoids only
Answer: A. Hyphae, collectively called mycelium
Explanation: The body of most fungi consists of long, slender, thread-like structures called hyphae, and the network of hyphae is called mycelium.
14. Yeast is an example of a fungus that is
A. Unicellular
B. Always multicellular with branched mycelium
C. Photosynthetic
D. Prokaryotic
Answer: A. Unicellular
Explanation: Yeast (Saccharomyces) is one of the few fungi that exist in a unicellular form, unlike most fungi which have a multicellular, filamentous mycelial structure.
15. A symbiotic association between fungi and algae is called
A. Lichen
B. Mycorrhiza
C. Mycelium
D. Rhizome
Answer: A. Lichen
Explanation: A lichen is a symbiotic association between a fungus (mycobiont) and a photosynthetic alga or cyanobacterium (phycobiont), where the fungus obtains food and the alga gets shelter and moisture.
16. A symbiotic association between fungi and the roots of higher plants is called
A. Mycorrhiza
B. Lichen
C. Mycelium
D. Hypha
Answer: A. Mycorrhiza
Explanation: Mycorrhiza is a symbiotic relationship between fungi and the roots of vascular plants, in which the fungus helps the plant absorb water and nutrients and receives food in return.
17. Viruses are considered to be at the boundary between living and non-living because they
A. Show no signs of life outside a host cell but can replicate inside a living host
B. Have a well-developed cellular structure like bacteria
C. Can carry out metabolism on their own outside a host cell
D. Never contain genetic material
Answer: A. Show no signs of life outside a host cell but can replicate inside a living host
Explanation: Viruses are inert (non-living) outside a host cell since they show no signs of metabolism, but once inside a living cell, they take over its machinery to replicate, showing living characteristics.
18. Viruses are considered obligate parasites because they
A. Can multiply only within a living host cell
B. Can multiply freely outside a host cell
C. Never require a host to survive
D. Are photosynthetic organisms
Answer: A. Can multiply only within a living host cell
Explanation: Viruses lack their own cellular machinery for reproduction, so they must infect a living host cell and use its machinery to multiply, making them obligate intracellular parasites.
19. The genetic material of a virus can be
A. Either DNA or RNA, but not both
B. Always DNA only
C. Always RNA only
D. Neither DNA nor RNA
Answer: A. Either DNA or RNA, but not both
Explanation: Unlike cellular organisms, which have both DNA and RNA, a virus contains only one type of nucleic acid—either DNA or RNA—as its genetic material.
20. The protein coat surrounding the nucleic acid of a virus is called
A. Capsid
B. Envelope
C. Nucleoid
D. Cell wall
Answer: A. Capsid
Explanation: The capsid is the protein coat that surrounds and protects the nucleic acid core of a virus, made up of small subunits called capsomeres.
21. Viroids differ from typical viruses mainly because viroids
A. Lack a protein coat and consist only of free RNA
B. Have a much larger genome than viruses
C. Contain both DNA and RNA together
D. Are actually a type of bacteria
Answer: A. Lack a protein coat and consist only of free RNA
Explanation: Viroids, discovered by T.O. Diener, consist of free RNA without a surrounding protein coat, unlike viruses, and have a much lower molecular weight.
22. Prions, associated with diseases like mad cow disease, are unusual infectious agents because they are
A. Abnormally folded proteins with no nucleic acid
B. Typical viruses containing DNA
C. Bacteria with a modified cell wall
D. Fungal spores
Answer: A. Abnormally folded proteins with no nucleic acid
Explanation: Prions are infectious agents made entirely of abnormally folded protein, with no genetic material (DNA or RNA), unlike all other known infectious agents.
23. Kingdom Plantae, in the five kingdom classification, includes organisms that are
A. Eukaryotic, chlorophyll-containing, and mostly autotrophic
B. Prokaryotic and heterotrophic
C. Eukaryotic but always non-photosynthetic
D. Unicellular only
Answer: A. Eukaryotic, chlorophyll-containing, and mostly autotrophic
Explanation: Kingdom Plantae comprises eukaryotic, multicellular organisms with chlorophyll, mostly photosynthetic (autotrophic), including algae, bryophytes, pteridophytes, gymnosperms, and angiosperms.
24. Kingdom Animalia includes organisms that are
A. Eukaryotic, multicellular, and heterotrophic
B. Prokaryotic and autotrophic
C. Eukaryotic but always photosynthetic
D. Unicellular and prokaryotic
Answer: A. Eukaryotic, multicellular, and heterotrophic
Explanation: Kingdom Animalia includes eukaryotic, multicellular, heterotrophic organisms that lack cell walls and depend directly or indirectly on plants for nutrition.
25. Why did scientists move away from the simple two-kingdom (Plantae and Animalia) classification system?
A. It failed to distinguish between prokaryotes and eukaryotes and between unicellular and multicellular organisms
B. It classified too many organisms as animals
C. It was based only on the color of organisms
D. It ignored the existence of species altogether
Answer: A. It failed to distinguish between prokaryotes and eukaryotes and between unicellular and multicellular organisms
Explanation: The two-kingdom system did not distinguish between prokaryotes and eukaryotes, unicellular and multicellular organisms, or photosynthetic (autotrophic) and non-photosynthetic (heterotrophic) organisms, leading to the need for more refined systems.
26. Bacteria that can survive in extremely salty environments are called
A. Halophiles
B. Thermoacidophiles
C. Methanogens
D. Chemoautotrophs
Answer: A. Halophiles
Explanation: Halophiles are a type of archaebacteria adapted to survive in extremely salty environments, such as salt lakes and marshes.
27. Bacteria found in the guts of ruminant animals like cattle, which produce methane gas, are called
A. Methanogens
B. Halophiles
C. Cyanobacteria
D. Nitrifying bacteria
Answer: A. Methanogens
Explanation: Methanogens are archaebacteria found in the gut of ruminant animals (like cows and buffaloes) responsible for the production of methane (biogas) from cellulose digestion.
28. Bacterial reproduction primarily occurs through
A. Fission (binary fission)
B. Sexual reproduction with fertilization
C. Budding exclusively
D. Spore formation exclusively
Answer: A. Fission (binary fission)
Explanation: Bacteria mainly reproduce asexually through fission (splitting into two), though they may also exhibit gene transfer through processes like conjugation.
29. Why are decomposer fungi like Rhizopus and Penicillium ecologically important?
A. They break down dead organic matter, recycling nutrients back into the ecosystem
B. They photosynthesize and produce oxygen for the ecosystem
C. They fix atmospheric nitrogen directly into the soil
D. They convert carbon dioxide into glucose for other organisms
Answer: A. They break down dead organic matter, recycling nutrients back into the ecosystem
Explanation: Saprophytic fungi like Rhizopus and Penicillium decompose dead and decaying organic matter, playing a crucial role in nutrient recycling within ecosystems.
30. Bacteriophages are viruses that specifically infect
A. Bacteria
B. Plants
C. Animals
D. Fungi
Answer: A. Bacteria
Explanation: Bacteriophages are a class of viruses that specifically infect bacterial cells, using them as hosts to replicate their genetic material.
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