Viruses, Viroids, Prions & Lichens — NEET Biology MCQs with Solutions
Free NEET Biology Viruses, Viroids, Prions & Lichens MCQs with step-by-step solutions (63 questions). Part of Biological Classification. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Viruses, Viroids, Prions & Lichens · easy · theory
Viruses are NOT included in the five-kingdom classification because they:
A. Are non-cellular and are inert (crystallisable) outside a host ✓ Correct
B. Are prokaryotic cells
C. Are eukaryotic cells
D. Have a true nucleus
Solution: Viruses are non-cellular, obligate intracellular parasites; outside a host they behave as inert crystals — so Whittaker left them out.
Q2 — Viruses, Viroids, Prions & Lichens · easy · theory
The genetic material of the Tobacco Mosaic Virus (TMV) is:
A. Both DNA and RNA
B. Protein
C. RNA ✓ Correct
D. DNA
Solution: Plant viruses usually have single-stranded RNA; animal viruses have ss or ds RNA or DNA.
Q3 — Viruses, Viroids, Prions & Lichens · easy · theory
The protein coat that protects the nucleic acid of a virus is called the:
A. Capsid ✓ Correct
B. Cell wall
C. Envelope of chitin
D. Pellicle
Solution: The capsid is made of subunits called capsomeres and protects the viral genome.
Q4 — Viruses, Viroids, Prions & Lichens · medium · theory
The term "virus" (meaning venom/poisonous fluid) and the discovery that the infectious agent could pass through bacteria-proof filters are credited respectively to:
A. Hooke; Pasteur
B. Stanley; Hooke
C. Beijerinck; Hooke
D. Pasteur; Ivanowsky/Beijerinck ✓ Correct
Solution: Pasteur coined "virus"; Ivanowsky and Beijerinck showed the agent passed bacterial filters (contagium vivum fluidum). Stanley later crystallised TMV.
Q5 — Viruses, Viroids, Prions & Lichens · medium · theory
Viroids differ from viruses in that they:
A. Consist of free RNA only, lacking a protein coat ✓ Correct
B. Are made only of protein
C. Have both DNA and a capsid
D. Are cellular
Solution: Viroids (discovered by Diener) are free, low-molecular-weight RNA without a protein coat — e.g. potato spindle tuber disease.
Q6 — Viruses, Viroids, Prions & Lichens · medium · theory
Lichens are a symbiotic association between:
A. Two fungi
B. Two algae
C. A plant and a bacterium
D. A fungus (mycobiont) and an alga/cyanobacterium (phycobiont) ✓ Correct
Solution: In lichens the algal partner makes food (autotroph) and the fungal partner provides shelter, water and minerals — a mutualism.
Q7 — Viruses, Viroids, Prions & Lichens · hard · theory
Prions are infectious agents responsible for diseases like BSE ("mad cow disease") and CJD. They are composed of:
A. Both DNA and protein
B. Abnormally folded protein (no nucleic acid) ✓ Correct
C. DNA only
D. RNA only
Solution: Prions are misfolded proteins that convert normal proteins to the abnormal form — they contain NO nucleic acid.
Q8 — Viruses, Viroids, Prions & Lichens · hard · theory
Lichens are good pollution indicators (especially of SO₂) because they:
A. Are unaffected by air quality
B. Only grow in cities
C. Do not grow in polluted areas ✓ Correct
D. Absorb all pollutants and thrive
Solution: Lichens are very sensitive to SO₂; their absence signals air pollution, making them reliable bioindicators.
Q9 — Viruses, Viroids, Prions & Lichens · hard · theory
Which statement about viral multiplication is CORRECT?
A. Viruses replicate only inside a living host, using the host machinery, after injecting/entering with their nucleic acid ✓ Correct
B. Viruses grow like bacteria on nutrient agar
C. Viruses possess their own ribosomes
D. Viruses divide by binary fission independently
Solution: Viruses are obligate intracellular parasites: they take over the host's biosynthetic machinery to replicate, having no ribosomes or metabolism of their own.
Q10 — Viruses, Viroids, Prions & Lichens · easy · numerical
A bacteriophage is a type of virus that specifically infects and multiplies within:
A. fungi
B. green plants
C. bacteria ✓ Correct
D. algae
Solution: The term bacteriophage literally means "bacteria eater"; these viruses attack bacterial cells.
Q11 — Viruses, Viroids, Prions & Lichens · easy · numerical
The protein coat of a virus (the capsid) is built up of numerous small repeating subunits called:
A. plasmids
B. nucleosomes
C. centromeres
D. capsomeres ✓ Correct
Solution: Capsomeres are the protein subunits that assemble into the viral capsid; the other terms belong to chromosomes or bacterial DNA.
Q12 — Viruses, Viroids, Prions & Lichens · medium · numerical
In a lichen, the algal partner and the fungal partner contribute respectively by:
A. the fungus preparing food by photosynthesis, and the alga absorbing water and minerals
B. the alga preparing food by photosynthesis, and the fungus absorbing water and minerals and providing shelter ✓ Correct
C. both partners absorbing organic food from the substratum
D. both partners photosynthesising equally to share food
Solution: In lichens the photosynthetic alga (phycobiont) makes food, while the fungus (mycobiont) provides shelter and absorbs water and minerals.
Q13 — Viruses, Viroids, Prions & Lichens · medium · numerical
Which of the following statements about prions is CORRECT?
A. They are the smallest known bacteria that lack a cell wall
B. They consist of a small circular free RNA molecule without a protein coat
C. They are abnormally folded proteins that convert normal proteins into the infectious form, causing diseases like BSE and CJD ✓ Correct
D. They possess a DNA genome enclosed within a protein capsid
Solution: Prions are infectious, abnormally folded proteins (no nucleic acid) that template misfolding of normal proteins, causing BSE and Creutzfeldt-Jakob disease; free RNA describes viroids and wall-less bacteria are mycoplasma.
Q14 — Viruses, Viroids, Prions & Lichens · medium · numerical
The Tobacco Mosaic Virus (TMV) stores its genetic information as single-stranded RNA within a helical protein coat. In contrast, a typical bacteriophage usually contains:
A. single-stranded RNA
B. double-stranded DNA ✓ Correct
C. single-stranded DNA
D. double-stranded RNA
Solution: Most bacteriophages (such as the T-even phages) carry double-stranded DNA as their genetic material, unlike the ssRNA of TMV.
Q15 — Viruses, Viroids, Prions & Lichens · medium · numerical
The scientist credited with first showing that viruses could be crystallised, and that the crystals were largely made of protein, was:
A. T.O. Diener
B. D.J. Ivanowsky
C. W.M. Stanley ✓ Correct
D. M.W. Beijerinck
Solution: W.M. Stanley (1935) crystallised TMV, demonstrating that viruses could be obtained as crystals; Ivanowsky and Beijerinck studied the transmissible sap, and Diener discovered viroids.
Q16 — Viruses, Viroids, Prions & Lichens · medium · numerical
Lichens are regarded as pioneer colonisers of bare rocks chiefly because they:
A. photosynthesise faster than any other organism on rock
B. store large quantities of water like mosses to keep the rock moist
C. secrete acids that weather the rock and help initiate soil formation ✓ Correct
D. fix atmospheric nitrogen and enrich the rock with nitrates
Solution: Lichens release acids that gradually break down (weather) the rock surface, beginning soil formation and paving the way for other organisms in ecological succession.
Q17 — Viruses, Viroids, Prions & Lichens · easy · theory
Fungus in association with algae forms lichens; fungus in association with roots of gymnosperms is called-
A. Mycoplasma
B. Commensalism
C. Mycorrhiza ✓ Correct
D. Parasite
Solution: A symbiotic fungus-root association is a mycorrhiza.
Q18 — Viruses, Viroids, Prions & Lichens · easy · theory
The viruses that infect bacteria are made up of:
A. Usually double stranded DNA ✓ Correct
B. Both single stranded DNA and double stranded RNA
C. Usually single stranded DNA
D. Usually double stranded RNA
Solution: Bacteriophages generally contain double stranded DNA.
Q19 — Viruses, Viroids, Prions & Lichens · medium · theory
Animal viruses have an inner core of:
A. Double stranded DNA
B. Either single or double stranded RNA
C. Either single/double stranded RNA or double stranded DNA ✓ Correct
D. Phosphoproteins
Solution: Animal viruses may have single- or double-stranded RNA or double-stranded DNA.
Q20 — Viruses, Viroids, Prions & Lichens · easy · theory
Sub-unit of coat (capsid) of a virus is:
A. Nucleotide
B. Capsomere ✓ Correct
C. None of these
D. Nucleosome
Solution: The capsid is made of protein subunits called capsomeres.
Q21 — Viruses, Viroids, Prions & Lichens · medium · theory
In R.H. Whittaker's system, viroids, prions & lichens are grouped into-
A. Monera
B. Protista and fungi
C. Protista
D. None of these ✓ Correct
Solution: Whittaker's five-kingdom system did not accommodate acellular entities like viroids, prions, or lichens.
Q22 — Viruses, Viroids, Prions & Lichens · easy · theory
Viruses were not placed in the classification because-
A. Lack of genetic material
B. All of these
C. Lack in study of viruses
D. They are not considered truly 'living' ✓ Correct
Solution: Being non-cellular obligate parasites that are inert outside a host, viruses are not regarded as truly living.
Q23 — Viruses, Viroids, Prions & Lichens · medium · theory
Viruses are not-
A. Active crystalline structure outside the living cell ✓ Correct
B. Once they infect a cell they take over the machinery of host cell to replicate themselves, killing the host
C. Non-cellular organism
D. Inert crystalline structure outside the living cell
Solution: Outside a host cell viruses are inert crystalline structures, not active ones.
Q24 — Viruses, Viroids, Prions & Lichens · medium · theory
The name 'virus', which means venom, was given by-
A. M.W. Beijerinck ✓ Correct
B. Pasteur
C. Stanley
D. Dmitri Ivanowsky
Solution: Beijerinck named the infectious agent 'virus' (meaning venom / poisonous fluid).
Q25 — Viruses, Viroids, Prions & Lichens · medium · theory
Who showed that viruses could be crystallized and crystals exist outside the host?
A. M.W. Beijerinck (1898)
B. Dmitri Ivanowsky (1892)
C. M.W. Stanley (1898)
D. W.M. Stanley (1935) ✓ Correct
Solution: Stanley (1935) crystallised the tobacco mosaic virus.
Q26 — Viruses, Viroids, Prions & Lichens · medium · theory
Which of the following is the major constituent in a crystallized virus structure?
A. Protein ✓ Correct
B. Nucleic acid
C. Fat
D. Carbohydrate
Solution: By mass, the protein capsid is the major constituent of a virus.
Q27 — Viruses, Viroids, Prions & Lichens · easy · theory
Viruses are-
A. Saprotroph
B. Obligate parasite ✓ Correct
C. Holozoic
D. Autotroph
Solution: Viruses can multiply only inside a living host, making them obligate parasites.
Q28 — Viruses, Viroids, Prions & Lichens · easy · theory
Genetic material of viruses is-
A. DNA and RNA both in an individual virus
B. DNA
C. DNA or RNA in an individual virus ✓ Correct
D. RNA
Solution: A given virus contains either DNA or RNA, never both.
Q29 — Viruses, Viroids, Prions & Lichens · medium · theory
The infectious material of viruses is-
A. All of these
B. Nucleoprotein
C. Protein coat
D. Genetic material ✓ Correct
Solution: The nucleic acid (genetic material) is the infectious component of a virus.
Q30 — Viruses, Viroids, Prions & Lichens · medium · theory
In general, viruses that infect plants have-
A. ds RNA
B. ss DNA
C. ds DNA
D. ss RNA ✓ Correct
Solution: Most plant viruses have single-stranded RNA.