Biological source, chemical nature and uses of cotton MCQs With Answer

Introduction

Understanding the biological source, chemical nature and uses of cotton is essential for B.Pharm students studying pharmaceutical excipients and raw materials. Cotton fibers originate from Gossypium species and are single-celled trichomes composed predominantly of cellulose — a linear β‑1,4‑linked D‑glucose polymer. Cotton linters and seed products supply cellulose for microcrystalline cellulose, carboxymethyl cellulose and cellulose acetate, while absorbent cotton and bleached cotton wool are used in wound care and sterile dressings. Cottonseed yields oil and protein-rich byproducts, although gossypol poses toxicity concerns. These MCQs cover botanical origin, fiber chemistry, processing, pharmaceutical applications and safety considerations to deepen conceptual and practical knowledge. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which genus is the primary biological source of commercial cotton used in pharmaceuticals?

• Glycine
• Gossypium
• Capsicum
• Cotoneaster

Correct Answer: Gossypium

Q2. Which two species supply the majority of global cotton fiber production?

• Gossypium arboreum and Gossypium herbaceum
• Gossypium hirsutum and Gossypium barbadense
• Gossypium tomentosum and Gossypium mustelinum
• Gossypium raimondii and Gossypium gossypioides

Correct Answer: Gossypium hirsutum and Gossypium barbadense

Q3. Cotton fiber is best described as which of the following plant structures?

• Multicellular seed coat fragments
• Single-celled epidermal trichome
• Vascular bundle
• Root hair

Correct Answer: Single-celled epidermal trichome

Q4. What is the principal chemical constituent of cotton fiber?

• Cellulose
• Lignin
• Keratin
• Pectin

Correct Answer: Cellulose

Q5. The repeating unit of cellulose is which monosaccharide linkage?

• α‑1,4 linked D‑glucose
• β‑1,4 linked D‑glucose
• α‑1,6 linked D‑galactose
• β‑1,3 linked D‑fructose

Correct Answer: β‑1,4 linked D‑glucose

Q6. Cotton linters are best defined as:

• Long primary fibers removed during spinning
• Short fibers remaining on seeds after ginning
• The oil extracted from cottonseed
• Waxy surface coating on mature fibers

Correct Answer: Short fibers remaining on seeds after ginning

Q7. Microcrystalline cellulose (MCC) used as a tablet excipient is commonly produced from:

• Cotton linters or purified cellulose
• Raw cotton fibers without processing
• Cottonseed oil
• Whole cottonseed meal

Correct Answer: Cotton linters or purified cellulose

Q8. Which pharmaceutical application directly uses bleached absorbent cotton wool?

• Capsule shell manufacturing
• Sterile wound dressings and swabs
• Active pharmaceutical ingredient synthesis
• Tablet coating

Correct Answer: Sterile wound dressings and swabs

Q9. Which impurity in cottonseed is known for its toxicity and requires processing precautions?

• Gossypol
• Phytic acid
• Caffeine
• Lactic acid

Correct Answer: Gossypol

Q10. Mercerization of cotton primarily results in which chemical/physical change?

• Conversion of cellulose I to cellulose II and increased fiber luster and reactivity
• Hydrolysis of cellulose to glucose
• Complete removal of cellulose leaving lignin-rich fibers
• Polymerization of cellulose chains to higher DP

Correct Answer: Conversion of cellulose I to cellulose II and increased fiber luster and reactivity

Q11. The chemical formula of the anhydroglucose unit in cellulose is:

• C6H12O6
• C6H10O5
• C5H10O5
• C6H8O4

Correct Answer: C6H10O5

Q12. Which chemical derivative of cellulose is commonly produced from cotton and used in pharmaceutical coatings and membranes?

• Cellulose acetate
• Polyethylene glycol
• Polyvinylpyrrolidone
• Starch acetate

Correct Answer: Cellulose acetate

Q13. Why is cotton a preferred raw material for high-purity cellulose in pharmaceuticals?

• High lignin content simplifies purification
• Low non-cellulosic impurity and high cellulose content
• It contains natural plasticizers that improve formulation
• Its natural oils act as preservatives

Correct Answer: Low non-cellulosic impurity and high cellulose content

Q14. During ginning, what primary separation occurs?

• Removal of fiber from seed
• Extraction of cottonseed oil
• Conversion of cellulose to MCC
• Bleaching of fibers

Correct Answer: Removal of fiber from seed

Q15. Which statement about cotton cellulose degree of polymerization (DP) is true?

• Cotton cellulose has very low DP (~50–200)
• Cotton cellulose has high DP (several thousand to ~10,000+), contributing to strength
• DP is irrelevant to mechanical properties
• Cotton cellulose DP is identical to starch

Correct Answer: Cotton cellulose has high DP (several thousand to ~10,000+), contributing to strength

Q16. Carboxymethyl cellulose (CMC), a viscosity modifier, is prepared from cellulose by which type of reaction?

• Oxidation to form aldehyde groups
• Etherification introducing carboxymethyl groups
• Hydrogenation of glucose units
• Radical polymerization

Correct Answer: Etherification introducing carboxymethyl groups

Q17. In pharmaceutical practice, sterile cotton wool must be processed to ensure which of the following?

• Retention of natural gossypol content
• Sterility and removal of particulate and pyrogenic contaminants
• High protein content for wound healing
• Preservation of native pigments

Correct Answer: Sterility and removal of particulate and pyrogenic contaminants

Q18. Which structural feature of cellulose enables extensive hydrogen bonding and crystallinity?

• Branched glycosidic linkages at C‑6
• Linear β‑1,4 glycosidic linkages with free hydroxyl groups
• Peptide cross-links between chains
• High sulphate ester content

Correct Answer: Linear β‑1,4 glycosidic linkages with free hydroxyl groups

Q19. Which of the following is not typically obtained from cottonseed processing?

• Cottonseed oil
• Cottonseed meal/protein
• Cellulose microfibrils for MCC directly from whole seed
• Gossypol as a secondary metabolite in seeds

Correct Answer: Cellulose microfibrils for MCC directly from whole seed

Q20. Which test reagent gives no characteristic blue color with cellulose but does with starch?

• Iodine–potassium iodide (I2/KI)
• Carmine staining
• ninhydrin
• Biuret reagent

Correct Answer: Iodine–potassium iodide (I2/KI)

Q21. The secondary cell wall of mature cotton fiber is primarily composed of:

• Lignin and hemicellulose
• Nearly pure cellulose (>90%)
• Cutin and waxes
• Proteinaceous matrix

Correct Answer: Nearly pure cellulose (>90%)

Q22. Which processing step is used to remove natural waxes, pectin and other impurities from cotton to obtain purified cellulose?

• Ginning
• Pulping and bleaching
• Cold pressing
• Fermentation

Correct Answer: Pulping and bleaching

Q23. Which property of microcrystalline cellulose (MCC) derived from cotton linters makes it excellent for direct compression tablets?

• High solubility in water
• Good compressibility and binding with plastic deformation
• High oil absorption capacity
• Strong reducing sugar activity

Correct Answer: Good compressibility and binding with plastic deformation

Q24. Which of the following correctly matches a cotton product to its common pharmaceutical use?

• Cottonseed oil — sterile absorbent dressings
• Cotton linters — microcrystalline cellulose production
• Raw cotton fiber — oral solid dosage excipient without processing
• Cottonseed meal — primary tablet binder

Correct Answer: Cotton linters — microcrystalline cellulose production

Q25. Cotton fiber strength and fineness are most directly influenced by which characteristic?

• Length and degree of cellulose crystallinity
• Seed oil content
• Presence of gossypol in fibers
• Chlorophyll concentration

Correct Answer: Length and degree of cellulose crystallinity

Q26. Which safety concern is most important when using cotton-derived materials in parenteral or sterile products?

• Residual pesticide and endotoxin contamination
• Excessive cellulose polymerization
• High lignin causing embolism
• Natural fragrance causing nausea

Correct Answer: Residual pesticide and endotoxin contamination

Q27. Which enzymatic activity would directly hydrolyze cellulose into glucose units?

• Amylase
• Cellulase
• Protease
• Lipase

Correct Answer: Cellulase

Q28. During development of cotton fiber, the massive deposition of cellulose occurs mainly in which stage?

• Primary wall formation only
• Secondary wall thickening stage
• Seed germination stage
• Leaf expansion stage

Correct Answer: Secondary wall thickening stage

Q29. Which modification increases aqueous solubility and is used to produce a water-soluble cellulose derivative from cotton?

• Esterification to cellulose acetate
• Carboxymethylation to form CMC
• Hydrogenation to form polyglucose
• Crosslinking to form insoluble gel

Correct Answer: Carboxymethylation to form CMC

Q30. Compared to wood pulp, cotton linters are preferred for some pharmaceutical cellulose derivatives mainly because they:

• Contain higher lignin content for strength
• Provide a higher purity cellulose with fewer hemicelluloses
• Are richer in proteins aiding formulation
• Yield more starch for binder production

Correct Answer: Provide a higher purity cellulose with fewer hemicelluloses

Download