Understanding organic non-metals in plant construction is essential for B.Pharm students studying plant-derived drugs, phytochemistry, and biomaterial properties. This concise guide covers roles of carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, and silicon in forming cell walls, lignin, proteins, nucleic acids, phospholipids and secondary metabolites. Focus is on structural functions, biosynthetic pathways, transport forms, deficiency and toxicity symptoms, and analytical methods used in pharmaceutical research. Emphasizing practical examples such as cellulose cross-linking, disulfide bonds in plant proteins, and phosphate esters in energy transfer helps link theory to drug development and extraction processes. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. Which non-metal forms the backbone of all organic molecules in plant construction?
- Oxygen
- Carbon
- Nitrogen
- Phosphorus
Correct Answer: Carbon
Q2. Which organic non-metal is most abundant by mass in plant cell walls and forms long β-1,4-glucan chains?
- Protein
- Cellulose (carbon and hydrogen polymer)
- Starch
- Lignin
Correct Answer: Cellulose (carbon and hydrogen polymer)
Q3. Phosphorus in plants is primarily found in which organic compounds important for energy transfer?
- Polysaccharides
- ATP and phosphate esters
- Carotenoids
- Terpenes
Correct Answer: ATP and phosphate esters
Q4. Which non-metal is essential for amino acids cysteine and methionine and helps form disulfide bonds in proteins?
- Sulfur
- Chlorine
- Silicon
- Phosphorus
Correct Answer: Sulfur
Q5. Which element is critical for nitrogen assimilation enzymes (nitrate reductase, nitrite reductase) activity due to its role in organic cofactors?
- Carbon
- Sulfur (in Fe-S clusters)
- Chlorine
- Silicon
Correct Answer: Sulfur (in Fe-S clusters)
Q6. Which non-metal contributes to membrane structure as part of phospholipids in plant cells?
- Phosphorus
- Chlorine
- Silicon
- Nitrogen
Correct Answer: Phosphorus
Q7. Which plant structural polymer is aromatic, rich in carbon and responsible for rigidity and water impermeability?
- Cellulose
- Lignin
- Pectin
- Hemicellulose
Correct Answer: Lignin
Q8. Chlorine in plants is mainly involved in which physiological process?
- Electron transport in photosystem II and osmoregulation
- Cellulose synthesis
- Lignin polymerization
- ATP synthesis in mitochondria
Correct Answer: Electron transport in photosystem II and osmoregulation
Q9. Silicon deposition in grasses forms structures called phytoliths; what is their primary role?
- Energy storage
- Structural support and herbivore defense
- Photosynthesis
- Protein synthesis
Correct Answer: Structural support and herbivore defense
Q10. Which analytical technique is commonly used for quantifying phosphorus and other non-metals in plant tissues with high sensitivity?
- Thin layer chromatography
- Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
- Gas chromatography
- Polarimetry
Correct Answer: Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
Q11. Organic nitrogen transported in phloem is mainly in which form?
- Nitrate
- Ammonium
- Amino acids (e.g., glutamine)
- Urea
Correct Answer: Amino acids (e.g., glutamine)
Q12. Which bond type formed by sulfur contributes to tertiary structure stabilization in plant proteins?
- Peptide bonds
- Disulfide bonds (S–S)
- Hydrogen bonds
- Glycosidic bonds
Correct Answer: Disulfide bonds (S–S)
Q13. Phosphate esters in sugars are crucial intermediates in which metabolic pathway relevant to plant construction?
- Glycolysis and Calvin cycle
- β-oxidation
- Isoprenoid synthesis
- Urea cycle
Correct Answer: Glycolysis and Calvin cycle
Q14. Deficiency of phosphorus in plants typically shows which symptom?
- Interveinal chlorosis of young leaves
- Darkening or purpling of older leaves and stunted growth
- Wilting due to root rot
- Excessive elongation and thin stems
Correct Answer: Darkening or purpling of older leaves and stunted growth
Q15. Which organic non-metal is the main electron acceptor in respiration and a major constituent of water and organic molecules?
- Hydrogen
- Oxygen
- Carbon
- Nitrogen
Correct Answer: Oxygen
Q16. Sulfur-containing secondary metabolites important in plant defense and pharmaceuticals include:
- Alkaloids
- Glucosinolates and thionins
- Terpenoids
- Flavonoids
Correct Answer: Glucosinolates and thionins
Q17. Which enzyme incorporates inorganic sulfate into organic molecules during sulfur assimilation?
- Sulfate adenylyltransferase and APS reductase pathway enzymes
- Nitrate reductase
- Rubisco
- ATP synthase
Correct Answer: Sulfate adenylyltransferase and APS reductase pathway enzymes
Q18. Which structural carbohydrate is soluble, gel-forming, and rich in galacturonic acid, contributing to cell adhesion?
- Hemicellulose
- Pectin
- Cellulose
- Lignin
Correct Answer: Pectin
Q19. Organic forms of phosphorus in plants include:
- Nitrate and nitrite
- Phosphate ions only
- Nucleotides, phospholipids, and sugar phosphates
- Free elemental phosphorus
Correct Answer: Nucleotides, phospholipids, and sugar phosphates
Q20. Which non-metal is a key constituent of chlorophyll molecules?
- Magnesium
- Nitrogen in the porphyrin ring
- Phosphorus
- Silicon
Correct Answer: Nitrogen in the porphyrin ring
Q21. In cell wall architecture, hemicellulose primarily interacts with which polymer to enhance structural integrity?
- Starch
- Cellulose microfibrils
- Proteins
- DNA
Correct Answer: Cellulose microfibrils
Q22. Which nitrogen assimilation enzyme converts ammonium and glutamate to glutamine, a major nitrogen donor?
- Glutamate dehydrogenase
- Glutamine synthetase
- Nitrate reductase
- Rubisco
Correct Answer: Glutamine synthetase
Q23. Which phosphorus-containing molecule is central to signal transduction via phosphorylation in plants?
- Sucrose
- ATP
- Cellulose
- Calcium carbonate
Correct Answer: ATP
Q24. Which method is commonly used to estimate total nitrogen content in plant samples for pharmaceutical studies?
- Kjeldahl method
- UV–Vis spectrophotometry for chlorophyll
- Thin layer chromatography
- Ninhydrin staining only
Correct Answer: Kjeldahl method
Q25. Lignin biosynthesis involves polymerization of which monomeric units?
- Glucose units
- Monolignols (coniferyl, sinapyl, p-coumaryl alcohols)
- Amino acids
- Fatty acids
Correct Answer: Monolignols (coniferyl, sinapyl, p-coumaryl alcohols)
Q26. Which non-metal plays a direct role in stomatal opening by contributing to osmotic balance?
- Phosphorus
- Chloride (Cl–)
- Carbon
- Silicon
Correct Answer: Chloride (Cl–)
Q27. Phytochemicals containing nitrogen important in pharmacology include:
- Terpenes
- Alkaloids
- Polyketides
- Cellulose derivatives
Correct Answer: Alkaloids
Q28. Which organic non-metal is central to forming hydrogen bonds that stabilize cellulose and protein structures?
- Nitrogen
- Hydrogen and oxygen (in hydrogen bonds)
- Phosphorus
- Sulfur
Correct Answer: Hydrogen and oxygen (in hydrogen bonds)
Q29. The organic non-metal responsible for phosphorylation of sugars during glycolysis in plants is derived from which molecule?
- ATP (adenosine triphosphate)
- Glucose-6-phosphate
- ADP
- NADH
Correct Answer: ATP (adenosine triphosphate)
Q30. Which sulfur-containing amino acid is a precursor of S-adenosylmethionine (SAM), a universal methyl donor?
- Cysteine
- Methionine
- Lysine
Correct Answer: Methionine
Q31. Which non-metal deficiency commonly causes interveinal chlorosis first in younger leaves due to immobility in the plant?
- Phosphorus
- Nitrogen
- Iron (Fe is a metal but symptom relates to Fe deficiency)
- Sulfur
Correct Answer: Iron (Fe is a metal but symptom relates to Fe deficiency)
Q32. In pharmaceutical extraction, understanding plant non-metal composition helps predict:
- Only the color of extracts
- Solubility, stability and interactions of metabolites
- Soil pH exclusively
- Seed germination rates only
Correct Answer: Solubility, stability and interactions of metabolites
Q33. Which non-metal is integral to the structure of nucleic acids as part of the sugar-phosphate backbone?
- Chlorine
- Phosphorus
- Sulfur
- Silicon
Correct Answer: Phosphorus
Q34. Which plant polymer provides elasticity and is rich in galactose and arabinose side chains?
- Cellulose
- Hemicellulose (e.g., arabinoxylans)
- Lignin
- Phospholipids
Correct Answer: Hemicellulose (e.g., arabinoxylans)
Q35. Which imaging method can visualize silica deposits or phytoliths in plant tissues used in pharmaceutical botany studies?
- Light microscopy with PAS stain
- Scanning Electron Microscopy (SEM)
- UV-visible spectrophotometry
- Thin layer chromatography
Correct Answer: Scanning Electron Microscopy (SEM)
Q36. Phospholipids in plant membranes contain which non-metal in their head group?
- Nitrogen (in choline/glycerophospho groups) and phosphorus
- Sulfur only
- Silicon only
- Chlorine only
Correct Answer: Nitrogen (in choline/glycerophospho groups) and phosphorus
Q37. Which organic non-metal is a limiting nutrient in many soils and often applied as fertilizer in the form of phosphate?
- Nitrogen
- Phosphorus
- Oxygen
- Sulfur
Correct Answer: Phosphorus
Q38. Organic sulfur in plant metabolism is commonly found in which cofactor involved in methylation?
- Glutathione
- S-adenosylmethionine (SAM)
- NADH
- ATP
Correct Answer: S-adenosylmethionine (SAM)
Q39. Which structural feature of cellulose allows for strong inter- and intramolecular hydrogen bonding?
- α-1,4 glycosidic linkages
- β-1,4 glycosidic linkages and free hydroxyl groups
- Branching like amylopectin
- High lignin content
Correct Answer: β-1,4 glycosidic linkages and free hydroxyl groups
Q40. In plants, nitrate reduction to ammonium occurs primarily in which cellular compartment?
- Mitochondria
- Cytosol and chloroplasts (nitrate reductase in cytosol, nitrite reductase in chloroplasts)
- Cell wall
- Vacuole
Correct Answer: Cytosol and chloroplasts (nitrate reductase in cytosol, nitrite reductase in chloroplasts)
Q41. Which non-metal-derived functional group in lignin monomers allows radical coupling during polymerization?
- Hydroxyl and methoxy (phenolic) groups
- Phosphate groups
- Carboxyl groups only
- Amide groups
Correct Answer: Hydroxyl and methoxy (phenolic) groups
Q42. Glutathione, a tripeptide important in redox balance, contains which key non-metal elements?
- Carbon, hydrogen, oxygen, nitrogen and sulfur
- Only carbon and hydrogen
- Only phosphorus and oxygen
- Only silicon and oxygen
Correct Answer: Carbon, hydrogen, oxygen, nitrogen and sulfur
Q43. Which plant-derived polymer rich in non-metal elements is especially resistant to chemical degradation and complicates extraction of drugs?
- Starch
- Lignin
- Sucrose
- Chitin
Correct Answer: Lignin
Q44. Which non-metal is a part of many plant cell wall glycoproteins as part of amino acid side chains?
- Phosphorus
- Sulfur (in cysteine/methionine residues and disulfide bonds)
- Silicon
- Chlorine
Correct Answer: Sulfur (in cysteine/methionine residues and disulfide bonds)
Q45. Which analytical method helps identify functional groups (e.g., phosphate, hydroxyl, carbonyl) in plant polymers?
- Fourier Transform Infrared Spectroscopy (FTIR)
- Mass spectrometry without ionization
- Kjeldahl method
- Gravimetric analysis only
Correct Answer: Fourier Transform Infrared Spectroscopy (FTIR)
Q46. Which role does silicon play in disease resistance of many crops?
- Acts as a nutrient directly in metabolism
- Deposits as silica reducing pathogen penetration and inducing resistance responses
- Replaces phosphorus in ATP
- Forms disulfide bonds in proteins
Correct Answer: Deposits as silica reducing pathogen penetration and inducing resistance responses
Q47. Which phosphorus-containing molecule is a structural component of RNA and DNA?
- Ribose
- Nucleoside triphosphates and phosphate backbone (phosphodiester bonds)
- Cellulose
- Chlorophyll
Correct Answer: Nucleoside triphosphates and phosphate backbone (phosphodiester bonds)
Q48. Which sulfur-containing compound serves as an antioxidant and participates in detoxification in plant cells?
- Ascorbic acid
- Glutathione
- Starch
- Phytate
Correct Answer: Glutathione
Q49. The term “organic non-metals” in plant construction most directly refers to:
- Metal ions chelated to proteins
- Elements like C, H, O, N, P, S incorporated into organic molecules and polymers
- Only gaseous elements in the atmosphere
- Inorganic salts in soil solutions
Correct Answer: Elements like C, H, O, N, P, S incorporated into organic molecules and polymers
Q50. Understanding interactions of organic non-metals in plant tissues helps B.Pharm students primarily by:
- Improving soil tillage techniques only
- Linking plant biochemistry to drug extraction, stability, formulation and quality control
- Designing irrigation systems exclusively
- Developing metal alloy implants
Correct Answer: Linking plant biochemistry to drug extraction, stability, formulation and quality control
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.
Mail- Sachin@pharmacyfreak.com