Polyploidy in medicinal plants is the condition of having extra chromosome sets that influences genetics, morphology and biosynthesis of therapeutic compounds. For B.Pharm students, mastering polyploidy links cytogenetics, pharmacognosy and plant biotechnology: definitions (autopolyploidy, allopolyploidy), induction methods (colchicine, oryzalin, tissue culture), detection techniques (flow cytometry, karyotyping, stomatal and pollen analysis) and pharmaceutical impacts on alkaloid, terpene and glycoside yields, chemotype variation and breeding strategies. Understanding mechanisms, analytical approaches and effects on drug precursor production is essential for quality control and drug development in medicinal species like Artemisia, Digitalis and Catharanthus. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is polyploidy?
- The presence of extra sets of chromosomes in a cell or organism
- A mutation affecting a single gene
- A type of fungal infection in plants
- Loss of all chromosomes in a cell
Correct Answer: The presence of extra sets of chromosomes in a cell or organism
Q2. Which statement best distinguishes autopolyploidy from allopolyploidy?
- Autopolyploidy arises from chromosome doubling within one species; allopolyploidy arises from interspecific hybridization followed by chromosome doubling
- Autopolyploidy involves hybridization; allopolyploidy arises only in bacteria
- Both terms describe loss of chromosomes rather than gains
- Allopolyploidy always reduces secondary metabolite content
Correct Answer: Autopolyploidy arises from chromosome doubling within one species; allopolyploidy arises from interspecific hybridization followed by chromosome doubling
Q3. Which antimitotic agent is classically used to induce polyploidy in plants?
- Colchicine
- Penicillin
- Glyphosate
- Ampicillin
Correct Answer: Colchicine
Q4. Which technique provides a rapid estimate of nuclear DNA content to detect polyploidy?
- Flow cytometry
- ELISA
- SDS-PAGE
- Light microscopy without staining
Correct Answer: Flow cytometry
Q5. How does polyploidy commonly affect secondary metabolite concentration in medicinal plants?
- It can increase production of some secondary metabolites by gene dosage and regulatory changes
- It uniformly eliminates all secondary metabolites
- It always reduces alkaloid content
- It has no possible effect on metabolite biosynthesis
Correct Answer: It can increase production of some secondary metabolites by gene dosage and regulatory changes
Q6. Formation of a tetraploid from a diploid parent typically involves which change?
- Doubling of the diploid chromosome number (2n → 4n)
- Loss of one chromosome (2n → 2n-1)
- Conversion of chromosomes to RNA
- Fusion of mitochondria only
Correct Answer: Doubling of the diploid chromosome number (2n → 4n)
Q7. Which morphological indicator is commonly used as a quick screen for polyploidy in plants?
- Increased stomatal and guard cell size
- Decreased leaf thickness only
- Reduced root length only
- Absence of chlorophyll in leaves
Correct Answer: Increased stomatal and guard cell size
Q8. What is a typical reproductive consequence of triploidy in plants?
- Reduced fertility or sterility due to irregular meiosis
- Enhanced self-fertility and seed set
- Conversion to diploid immediately
- Complete immunity to pathogens
Correct Answer: Reduced fertility or sterility due to irregular meiosis
Q9. Allopolyploidy most often results from which process?
- Hybridization between two species followed by chromosome doubling
- Viral infection of meristematic tissue
- Somatic mutation in a single gene
- Complete elimination of chloroplasts
Correct Answer: Hybridization between two species followed by chromosome doubling
Q10. Which cytogenetic method allows direct counting of chromosome numbers to confirm ploidy?
- Karyotyping (chromosome counting)
- Mass spectrometry
- Immunohistochemistry
- Northern blotting
Correct Answer: Karyotyping (chromosome counting)
Q11. Flow cytometry measures which cellular parameter relevant to ploidy analysis?
- Relative nuclear DNA content
- Respiration rate in mitochondria
- Cell membrane lipid composition
- Protein tertiary structure
Correct Answer: Relative nuclear DNA content
Q12. Gene expression changes following polyploidy are primarily attributed to what?
- Gene dosage effects and regulatory network alterations
- Complete gene deletion exclusively
- Only chloroplast genome changes
- Immediate loss of transcript processing
Correct Answer: Gene dosage effects and regulatory network alterations
Q13. Which medicinal species has been studied for increased artemisinin production via induced polyploidy?
- Artemisia annua
- Atropa belladonna
- Papaver somniferum
- Ginkgo biloba
Correct Answer: Artemisia annua
Q14. What is the primary cellular mechanism by which colchicine induces polyploidy?
- Disruption of spindle microtubule polymerization during mitosis
- Enhancement of DNA repair enzymes
- Activation of photosynthesis genes
- Inhibition of cell wall synthesis
Correct Answer: Disruption of spindle microtubule polymerization during mitosis
Q15. Compared to colchicine, oryzalin is often preferred because:
- It is effective at lower concentrations and more plant-specific in blocking microtubules
- It is an antibiotic that increases growth rate
- It causes targeted gene deletions
- It permanently prevents any further cell division forever
Correct Answer: It is effective at lower concentrations and more plant-specific in blocking microtubules
Q16. What meiotic configuration is commonly observed in newly formed autopolyploids that complicates inheritance?
- Multivalent pairing of homologous chromosomes
- Perfect bivalent pairing without errors
- Complete absence of synapsis
- Only univalent chromosomes with no pairing
Correct Answer: Multivalent pairing of homologous chromosomes
Q17. The basic chromosome number is represented by which symbol in cytogenetics?
- x (lowercase x)
- n (haploid gametic number only)
- p (ploidy factor)
- z (zygosity index)
Correct Answer: x (lowercase x)
Q18. Somatic hybridization by protoplast fusion can produce plants analogous to which ploidy category?
- Allopolyploids combining two distinct nuclear genomes
- Aneuploid plants with single chromosome loss
- Only diploid plants irrespective of fusion partners
- Mitochondrial polyploids only
Correct Answer: Allopolyploids combining two distinct nuclear genomes
Q19. Which analytical method is essential to assess changes in secondary metabolite profiles after inducing polyploidy?
- GC-MS or HPLC metabolite profiling
- Gram staining
- ELISA for serum proteins
- Light scattering particle sizing
Correct Answer: GC-MS or HPLC metabolite profiling
Q20. What process refers to the stabilization of meiotic behavior in newly formed polyploids over generations?
- Diploidization
- Dehydration
- Fragmentation
- Endosymbiosis
Correct Answer: Diploidization
Q21. How does cell size typically change with increased ploidy level?
- Cell size generally increases with higher ploidy
- Cell size becomes microscopic and irreversibly shrinks
- Cell size remains exactly the same always
- Cell walls disappear
Correct Answer: Cell size generally increases with higher ploidy
Q22. How does aneuploidy differ from polyploidy?
- Aneuploidy is gain or loss of individual chromosomes; polyploidy is gain of whole chromosome sets
- Aneuploidy is only observed in fungi; polyploidy only in animals
- Aneuploidy doubles the entire genome; polyploidy deletes single chromosomes
- They are synonyms and mean the same thing
Correct Answer: Aneuploidy is gain or loss of individual chromosomes; polyploidy is gain of whole chromosome sets
Q23. Endopolyploidy is best described as:
- Cells undergoing DNA replication without subsequent cell division, leading to increased nuclear DNA content
- Complete elimination of nuclear DNA from cells
- Fusion of pollen tubes during fertilization
- Production of endophytic bacteria
Correct Answer: Cells undergoing DNA replication without subsequent cell division, leading to increased nuclear DNA content
Q24. A major practical challenge with induced polyploid lines for pharmaceutical use is:
- Genetic instability and somaclonal variation affecting consistency
- Immediate and universal safety approval by regulators
- Guaranteed increase in all therapeutic compounds
- Complete resistance to environmental stress
Correct Answer: Genetic instability and somaclonal variation affecting consistency
Q25. In tissue culture, which approach is commonly used to induce polyploidy in shoot cultures?
- Treatment of apical meristems or cultured shoots with colchicine or oryzalin
- Adding high sugar concentrations to the medium alone
- Exposing cultures only to visible light without chemicals
- Feeding cultures with antibiotics indefinitely
Correct Answer: Treatment of apical meristems or cultured shoots with colchicine or oryzalin
Q26. Why might polyploidy change a plant’s chemotype relevant to drug extraction?
- Because altered gene dosage and regulation can shift enzyme expression in biosynthetic pathways
- Because polyploidy destroys all biosynthetic enzymes
- Because polyploidy only affects root architecture and never metabolism
- Because polyploidy converts secondary metabolites into proteins
Correct Answer: Because altered gene dosage and regulation can shift enzyme expression in biosynthetic pathways
Q27. Which practical advantage do many triploid fruit cultivars show despite reduced fertility?
- Seedlessness or reduced seed formation desirable for fruit quality
- Increased ability to fix atmospheric nitrogen
- Ability to photosynthesize in complete darkness
- Immediate conversion into polyunsaturated fats
Correct Answer: Seedlessness or reduced seed formation desirable for fruit quality
Q28. For pharmaceutical-grade production from polyploid medicinal plants, regulatory quality control must prioritize:
- Consistent chemotype and quantified active constituent content via validated assays
- Only morphological uniformity without chemical testing
- Ignoring genetic background entirely
- Assuming higher ploidy guarantees safety without testing
Correct Answer: Consistent chemotype and quantified active constituent content via validated assays
Q29. Which parameter measured by flow cytometry increases proportionally with ploidy level?
- Nuclear DNA content (C-value)
- Chlorophyll fluorescence lifetime only
- Cell wall cellulose crystallinity exclusively
- Number of stomata per unit area decreases proportionally
Correct Answer: Nuclear DNA content (C-value)
Q30. To distinguish between autopolyploid and allopolyploid origin, which cytogenetic/molecular tool is most informative?
- Genomic in situ hybridization (GISH) to detect parental genomes
- Gram staining of leaf tissue
- Simple measurement of plant height only
- Counting root hairs per cm
Correct Answer: Genomic in situ hybridization (GISH) to detect parental genomes
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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