Chemical nature of carbohydrates MCQs With Answer

Chemical nature of carbohydrates MCQs With Answer is an essential study area for B. Pharm students focusing on structure, stereochemistry, reactions and pharmaceutical relevance of sugars. This introduction covers monosaccharides, disaccharides and polysaccharides, glycosidic bonds, anomers, epimers, reducing versus non‑reducing sugars, and common functional derivatives like sugar alcohols, amino sugars and deoxy sugars. Emphasis is on chemical behaviour, identification tests and implications for drug formulation and glycoside prodrugs. Keywords: Chemical nature of carbohydrates MCQs With Answer, carbohydrates, monosaccharides, polysaccharides, glycosidic bond, stereochemistry, B. Pharm. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which empirical formula best represents most simple monosaccharides?

• CH2O
• Cn(H2O)n
• CnHnOn
• CH2O2

Correct Answer: Cn(H2O)n

Q2. Which term classifies a sugar containing an aldehyde functional group?

• Ketose
• Epimer
• Aldose
• Anomer

Correct Answer: Aldose

Q3. Which triose is an aldose commonly involved in central metabolism?

• Dihydroxyacetone
• Glyceraldehyde
• Erythrulose
• Ribulose

Correct Answer: Glyceraldehyde

Q4. What is the configuration descriptor for the stereochemistry of naturally occurring glucose?

• L‑configuration
• D‑configuration
• R‑configuration
• S‑configuration

Correct Answer: D‑configuration

Q5. The carbonyl carbon in cyclic monosaccharides that becomes a new stereocentre is called:

• Chiral carbon
• Anomeric carbon
• Carboxyl carbon
• Carbonyl oxygen

Correct Answer: Anomeric carbon

Q6. Mutarotation in glucose results from:

• Interconversion between open chain and cyclic forms
• Oxidation of the aldehyde group
• Hydrolysis of glycosidic bonds
• Epimerisation at C‑4

Correct Answer: Interconversion between open chain and cyclic forms

Q7. Which cyclic ring forms are common for hexoses like glucose?

• Pyranose and furanose
• Piperidine and furanose
• Pyridine and furanose
• Thiopyranose and furanose

Correct Answer: Pyranose and furanose

Q8. Which disaccharide is connected by an α(1→4) glycosidic bond and is reducing?

• Sucrose
• Lactose
• Maltose
• Cellobiose

Correct Answer: Maltose

Q9. Which disaccharide is non‑reducing due to involvement of both anomeric carbons?

• Maltose
• Sucrose
• Lactose
• Isomaltose

Correct Answer: Sucrose

Q10. Cellulose differs from starch primarily by which bond type?

• α(1→4) glycosidic bonds
• β(1→4) glycosidic bonds
• α(1→6) branching bonds
• β(1→6) branching bonds

Correct Answer: β(1→4) glycosidic bonds

Q11. Which sugar alcohol is commonly used as a pharmaceutical excipient and osmotic diuretic?

• Sorbitol
• Ribitol
• Xylulose
• Fructose

Correct Answer: Sorbitol

Q12. An epimer is defined as sugars that differ in configuration at how many stereocentres?

• All stereocentres
• Exactly one stereocentre
• No stereocentres
• Two stereocentres

Correct Answer: Exactly one stereocentre

Q13. Which pair are C‑4 epimers commonly encountered in carbohydrate chemistry?

• Glucose and mannose
• Glucose and galactose
• Glucose and fructose
• Mannose and fructose

Correct Answer: Glucose and galactose

Q14. Formation of a glycoside from a monosaccharide involves conversion of the hemiacetal at the anomeric carbon into:

• A hemiacetal
• An acetal
• An aldehyde
• A ketone

Correct Answer: An acetal

Q15. Which reagent is typically used to distinguish between reducing and non‑reducing sugars?

• Seliwanoff’s reagent
• Benedict’s or Fehling’s reagent
• Bial’s reagent
• Biuret reagent

Correct Answer: Benedict’s or Fehling’s reagent

Q16. Seliwanoff’s test is useful to distinguish:

• Reducing from non‑reducing sugars
• Aldoses from ketoses
• Pentoses from hexoses
• Monosaccharides from polysaccharides

Correct Answer: Aldoses from ketoses

Q17. Bial’s test specifically detects which class of sugars?

• Hexoses
• Deoxy sugars
• Pentoses
• Amino sugars

Correct Answer: Pentoses

Q18. Which derivative is formed when sugars react with phenylhydrazine?

• Glycoside
• Osazone
• Aldol
• Acetal

Correct Answer: Osazone

Q19. Deoxy sugars such as 2‑deoxyribose lack which functional group at C‑2?

• Hydroxyl group
• Anomeric hydroxyl
• Carbonyl group
• Methyl group

Correct Answer: Hydroxyl group

Q20. Amino sugars like glucosamine have which substitution on the sugar ring?

• Carboxyl group at C‑6
• Amino group replacing a hydroxyl
• Additional methyl group
• Double bond between C‑2 and C‑3

Correct Answer: Amino group replacing a hydroxyl

Q21. Which statement correctly describes a reducing sugar?

• Contains a free hemiacetal or hemiketal capable of opening to an aldehyde or ketone
• Has all hydroxyls involved in glycosidic bonds
• Is only present in polysaccharides
• Cannot be oxidised by mild oxidising agents

Correct Answer: Contains a free hemiacetal or hemiketal capable of opening to an aldehyde or ketone

Q22. Which sugar is the primary blood sugar and a principal monosaccharide in pharmaceutical contexts?

• Fructose
• Glucose
• Sucrose
• Maltose

Correct Answer: Glucose

Q23. The glycosidic bond between glucose units in amylose is primarily:

• α(1→4)
• β(1→4)
• α(1→6)
• β(1→6)

Correct Answer: α(1→4)

Q24. Glycogen differs from amylopectin by:

• Having only β(1→4) bonds
• Having more frequent α(1→6) branch points
• Being a disaccharide
• Containing fructose residues

Correct Answer: Having more frequent α(1→6) branch points

Q25. In Haworth projection, the substituent on the right in Fischer projection typically appears:

• Above the plane
• Below the plane
• At the anomeric position
• At C‑1 only

Correct Answer: Below the plane

Q26. Which monosaccharide gives a positive Tollens’ test?

• Non‑reducing disaccharide
• A reducing sugar like glucose
• All sugar alcohols
• Only ketoses

Correct Answer: A reducing sugar like glucose

Q27. Which modification increases water solubility and is used as a sweetener and excipient: conversion of glucose to?

• Cellulose
• Sorbitol
• Starch
• Glycogen

Correct Answer: Sorbitol

Q28. A β‑glycosidic bond indicates that the substituent at the anomeric carbon is oriented:

• Opposite to the CH2OH group
• On the same side as the CH2OH group
• Always axial
• Not involved in ring closure

Correct Answer: On the same side as the CH2OH group

Q29. Which sugar is a ketose commonly found in sucrose and fructose metabolism?

• Glucose
• Fructose
• Galactose
• Mannose

Correct Answer: Fructose

Q30. Hydrolysis of a glycoside yields:

• Alcohol and alkene
• A sugar and an aglycone (non‑sugar part)
• Two amino acids
• An osazone derivative

Correct Answer: A sugar and an aglycone (non‑sugar part)

Q31. Which carbohydrate derivative is commonly used as a sweetener that is poorly metabolised by humans?

• Sorbitol
• Xylitol
• Lactose
• Starch

Correct Answer: Xylitol

Q32. In Fischer projection, the highest‑numbered chiral carbon determines:

• Optical rotation sign (+/−)
• D or L configuration
• Number of anomers
• Ring size preference

Correct Answer: D or L configuration

Q33. Which test uses resorcinol and hydrochloric acid to detect ketose sugars?

• Benedict’s test
• Seliwanoff’s test
• Bial’s test
• Bromine water test

Correct Answer: Seliwanoff’s test

Q34. The term “reducing end” in polysaccharides refers to:

• The end bearing a free anomeric carbon capable of ring opening
• The terminal carbon bonded to methyl
• The branched point of polymer
• The non‑anomeric terminal hydroxyl

Correct Answer: The end bearing a free anomeric carbon capable of ring opening

Q35. Which monosaccharide unit is characteristic of bacterial cell wall peptidoglycan?

• Glucuronic acid and N‑acetylglucosamine
• Fructose and mannose
• Sorbitol and xylitol
• Ribose and deoxyribose

Correct Answer: Glucuronic acid and N‑acetylglucosamine

Q36. Lactose intolerance results from deficiency of which enzyme?

• Sucrase
• Amylase
• Lactase (β‑galactosidase)
• Invertase

Correct Answer: Lactase (β‑galactosidase)

Q37. Phosphate esters of sugars (e.g., glucose‑6‑phosphate) are important because they:

• Are nonpolar and cross cell membranes easily
• Activate sugars for metabolism and prevent membrane escape
• Are used only for structural polysaccharides
• Convert sugars into amino acids

Correct Answer: Activate sugars for metabolism and prevent membrane escape

Q38. Which sugar acid results from oxidation of the primary alcohol at C‑6 of glucose?

• Gluconic acid
• Glucuronic acid
• Galacturonic acid
• Fructonic acid

Correct Answer: Glucuronic acid

Q39. In drug design, glycosylation of small molecules often improves:

• Lipophilicity and membrane permeability
• Solubility and targeted delivery via transporters
• Thermal stability only
• Ability to form osazones

Correct Answer: Solubility and targeted delivery via transporters

Q40. The anomeric carbon in pyranose is typically which numbered carbon in aldohexoses?

• C‑1
• C‑2
• C‑5
• C‑6

Correct Answer: C‑1

Q41. Which monosaccharide is the component of lactose?

• Glucose and fructose
• Glucose and galactose
• Glucose and mannose
• Fructose and galactose

Correct Answer: Glucose and galactose

Q42. Which linkage is responsible for branching in glycogen?

• α(1→4)
• α(1→6)
• β(1→4)
• β(1→6)

Correct Answer: α(1→6)

Q43. Which sugar component is found in nucleotides of RNA?

• 2‑Deoxyribose
• Ribose
• Glucose
• Fructose

Correct Answer: Ribose

Q44. Which statement about Haworth and Fischer projections is correct?

• Haworth shows open chain, Fischer shows ring
• Fischer shows open chain, Haworth shows cyclic ring
• Both represent rings only
• Neither depict stereochemistry

Correct Answer: Fischer shows open chain, Haworth shows cyclic ring

Q45. Which monosaccharide is an important precursor for amino sugar synthesis and glycosaminoglycans?

• Glucosamine
• Xylitol
• Sorbitol
• Fructose

Correct Answer: Glucosamine

Q46. The reaction of sugars with ammonia or amines to form N‑substituted derivatives typically involves which carbon?

• Anomeric carbon only
• C‑2 hydroxyl (for amino sugars) or oxidation products depending on pathway
• C‑6 methylation
• Elimination at C‑3

Correct Answer: C‑2 hydroxyl (for amino sugars) or oxidation products depending on pathway

Q47. Which polysaccharide is primarily used by plants for energy storage?

• Cellulose
• Starch (amylose/amylopectin)
• Chitin
• Hyaluronic acid

Correct Answer: Starch (amylose/amylopectin)

Q48. Which monosaccharide is a common reducing sugar with a free aldehyde group in its open chain form?

• Sucrose
• Glucose
• Trehalose
• Sorbitol

Correct Answer: Glucose

Q49. Glycosaminoglycans (GAGs) are rich in which types of sugar derivatives?

• Neutral hexoses only
• Uronic acids and N‑acetylated amino sugars
• Only deoxysugars
• Only pentoses

Correct Answer: Uronic acids and N‑acetylated amino sugars

Q50. Which structural feature allows cellulose fibers to have high tensile strength?

• α(1→4) branching
• Extensive hydrogen bonding between β(1→4) linked chains
• Presence of many anomeric glycosides
• High content of deoxy sugars

Correct Answer: Extensive hydrogen bonding between β(1→4) linked chains

G S Sachin

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