Quick revision: every question with its correct answer. For the full explanation, open the relevant test and tap View Solution.
10.3 Secondary Metabolites — Test 1
Q1. Terpenoids are made of which repeating building-block units?✓ Isoprene
Q2. Secondary metabolites are best defined as compounds that:✓ Are not directly required for growth but aid survival, defence and signalling
Q3. Which of the following is the correct broad classification of plant secondary metabolites?✓ Phenolics, terpenoids and nitrogen-containing compounds (alkaloids)
Q4. Alkaloids are nitrogen-containing secondary metabolites mostly derived from:✓ Amino acids
Q5. Which of the following is an alkaloid?✓ Morphine
Q6. Flavonoids belong to which class of secondary metabolites?✓ Phenolics
Q7. The phenylpropanoid pathway, which gives rise to many phenolics, starts from which amino acid?✓ Phenylalanine
Q8. Lignin, a major structural phenolic polymer of plant cell walls, functions mainly to:✓ Provide mechanical strength and water-conducting rigidity
Q9. Which secondary metabolite class includes essential oils responsible for plant aromas?✓ Terpenoids
Q10. Natural rubber is a secondary metabolite chemically classified as a:✓ Polyterpene (polyisoprene)
Q11. Gums and pectins, used commercially as gelling/thickening agents, are chemically:✓ Polysaccharide-based secondary products
Q12. Tannins, which give astringency and act in plant defence, are classified as:✓ Phenolic compounds
Q13. The universal five-carbon precursors for all terpenoid biosynthesis are:✓ Isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP)
Q14. Caffeine, theobromine and theophylline are secondary metabolites of which class?✓ Purine alkaloids
Q15. Anthocyanins, the water-soluble pigments giving red/purple/blue colours to flowers and fruits, are:✓ Flavonoids (phenolics)
Q16. Which terpenoid pigment is the precursor of vitamin A and a major plant secondary metabolite?✓ β-carotene
Q17. Phytoalexins are secondary metabolites that plants produce mainly in response to:✓ Microbial/pathogen attack
Q18. Glycosides such as the cardiac glycoside digoxin consist of a sugar moiety attached to a(n):✓ Non-sugar aglycone
Q19. Which biosynthetic pathway provides the isoprene units for terpenoids in the plant cytosol?✓ Mevalonate (MVA) pathway
Q20. A common biological/commercial application of plant alkaloids is as:✓ Pharmaceuticals (drugs) and stimulants