Biological role of carbohydrates MCQs With Answer provides B. Pharm students a focused review of carbohydrate biochemistry, metabolism, and clinical relevance. This concise, SEO-friendly introduction explains key topics—energy metabolism, glycolysis, gluconeogenesis, glycogen storage, pentose phosphate pathway, glycoproteins, and carbohydrate digestion/absorption—while highlighting pharmacological and pathophysiological implications such as diabetes, inborn errors, and drug metabolism. Carefully crafted MCQs reinforce understanding of structure-function relationships, enzymatic mechanisms, transporters (SGLT/GLUT), and diagnostic assays. Ideal for exam prep and revision, these practice questions emphasize depth and application to pharmacy practice. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. Which monosaccharide is the primary energy source for brain cells?
- Glucose
- Fructose
- Galactose
- Lactose
Correct Answer: Glucose
Q2. Which disaccharide is non-reducing and does not give a positive Benedict’s test?
- Glucose
- Sucrose
- Fructose
- Maltose
Correct Answer: Sucrose
Q3. Where is glycogen primarily stored in the human body for short-term glucose supply?
- Liver and skeletal muscle
- Pancreas
- Adipose tissue only
- Bone marrow
Correct Answer: Liver and skeletal muscle
Q4. Which enzyme begins starch digestion in the mouth?
- Salivary amylase (ptyalin)
- Sucrase
- Lactase
- Maltase
Correct Answer: Salivary amylase (ptyalin)
Q5. What type of glycosidic linkage forms cellulose chains?
- Alpha-1,4 glycosidic bonds
- Alpha-1,6 glycosidic bonds
- Beta-1,4 glycosidic bonds
- Beta-1,6 glycosidic bonds
Correct Answer: Beta-1,4 glycosidic bonds
Q6. Which polysaccharide is the main storage form of glucose in plants?
- Starch
- Glycogen
- Cellulose
- Chitin
Correct Answer: Starch
Q7. Besides NADPH, what key metabolite is produced by the pentose phosphate pathway?
- Pyruvate
- Ribose-5-phosphate
- Acetyl-CoA
- Glucose-6-phosphate
Correct Answer: Ribose-5-phosphate
Q8. Which enzyme converts glucose-6-phosphate to fructose-6-phosphate in glycolysis?
- Hexokinase
- Phosphoglucose isomerase
- Phosphofructokinase-1
- Aldolase
Correct Answer: Phosphoglucose isomerase
Q9. Which glucose transporter is insulin-responsive and important in muscle and adipose tissue?
- GLUT1
- GLUT2
- GLUT4
- SGLT1
Correct Answer: GLUT4
Q10. Which monosaccharide is the C4 epimer of glucose?
- Mannose
- Galactose
- Fructose
- Ribose
Correct Answer: Galactose
Q11. Glycogen phosphorylase catalyzes which reaction during glycogen breakdown?
- Hydrolysis of alpha-1,6 bonds at branch points
- Removal of glucose residues as glucose-1-phosphate from alpha-1,4 chains
- Conversion of glucose to glucose-6-phosphate
- Formation of UDP-glucose for glycogen synthesis
Correct Answer: Removal of glucose residues as glucose-1-phosphate from alpha-1,4 chains
Q12. Which activated sugar donor is essential for glycogen synthesis?
- UDP-glucose
- ATP-glucose
- NADH-glucose
- GTP-glucose
Correct Answer: UDP-glucose
Q13. Classic galactosemia is caused by deficiency of which enzyme?
- Galactokinase
- Galactose-1-phosphate uridylyltransferase (GALT)
- Uridine diphosphate galactose epimerase
- Lactase
Correct Answer: Galactose-1-phosphate uridylyltransferase (GALT)
Q14. Which hepatic enzyme phosphorylates fructose to fructose-1-phosphate during fructose metabolism?
- Fructokinase
- Hexokinase
- Aldolase B
- Sorbitol dehydrogenase
Correct Answer: Fructokinase
Q15. In gluconeogenesis, which enzyme converts oxaloacetate to phosphoenolpyruvate?
- Pyruvate kinase
- PEP carboxykinase (PEPCK)
- Pyruvate dehydrogenase
- Phosphoenolpyruvate hydratase
Correct Answer: PEP carboxykinase (PEPCK)
Q16. Which hormone stimulates hepatic glycogenolysis and increases blood glucose?
- Insulin
- Glucagon
- Aldosterone
- Prolactin
Correct Answer: Glucagon
Q17. Which of the following is not a monosaccharide?
- Glucose
- Fructose
- Sucrose
- Galactose
Correct Answer: Sucrose
Q18. ABO blood group antigens are determined by which molecular structures on RBCs?
- Polypeptide hormone receptors
- Oligosaccharide chains on membrane glycoproteins/glycolipids
- Sulfated proteoglycans
- Lipid-only bilayer composition
Correct Answer: Oligosaccharide chains on membrane glycoproteins/glycolipids
Q19. Which enzyme hydrolyzes lactose into glucose and galactose in the small intestine?
- Maltase
- Lactase
- Sucrase
- Amylase
Correct Answer: Lactase
Q20. The main biochemical role of the hexose monophosphate (HMP) shunt is:
- ATP generation
- NADPH production for biosynthesis and antioxidant defense
- Direct synthesis of glycogen
- Conversion of pyruvate to acetyl-CoA
Correct Answer: NADPH production for biosynthesis and antioxidant defense
Q21. The glycosidic bond in maltose is:
- Alpha-1,2
- Alpha-1,4
- Beta-1,4
- Alpha-1,6
Correct Answer: Alpha-1,4
Q22. Which dietary carbohydrate is non-digestible by human enzymes and promotes gut health?
- Cellulose (dietary fiber)
- Maltose
- Sucrose
- Glycogen
Correct Answer: Cellulose (dietary fiber)
Q23. Which disaccharide has a free anomeric carbon and is therefore a reducing sugar?
- Sucrose
- Maltose
- Trehalose
- Cellulose
Correct Answer: Maltose
Q24. Which enzyme has both transferase and alpha-1,6-glucosidase activities to debranch glycogen?
- Glycogen phosphorylase
- Debranching enzyme (glycogen debranching enzyme)
- Branching enzyme
- Glycogen synthase
Correct Answer: Debranching enzyme (glycogen debranching enzyme)
Q25. Which pathway provides ribose sugars required for nucleotide biosynthesis?
- Glycolysis
- Pyrimidine synthesis pathway
- Pentose phosphate pathway
- Citric acid cycle
Correct Answer: Pentose phosphate pathway
Q26. Which sugar alcohol is formed by reduction of glucose and accumulates in diabetic complications?
- Sorbitol
- Mannitol
- Isomalt
- Xylitol
Correct Answer: Sorbitol
Q27. The linear, rigid structure of cellulose is due to which feature?
- Alpha-1,4 linkages causing branching
- Beta-1,4 linkages enabling extensive hydrogen bonding between chains
- Alpha-1,6 branching points every 8 residues
- Sulfated side chains preventing packing
Correct Answer: Beta-1,4 linkages enabling extensive hydrogen bonding between chains
Q28. Deficiency of which enzyme causes Pompe disease (Glycogen Storage Disease type II)?
- Liver glycogen phosphorylase
- Lysosomal alpha-1,4-glucosidase (acid maltase)
- Dysfunctional branching enzyme
- Debranching enzyme
Correct Answer: Lysosomal alpha-1,4-glucosidase (acid maltase)
Q29. Which hexokinase isoform in the liver has a high Km and serves as a glucose sensor?
- Hexokinase I
- Hexokinase II
- Glucokinase (hexokinase IV)
- Hexokinase III
Correct Answer: Glucokinase (hexokinase IV)
Q30. Which enzyme catalyzes the rate-limiting first step of the oxidative branch of the pentose phosphate pathway?
- Glucose-6-phosphate dehydrogenase (G6PD)
- 6-Phosphogluconate dehydrogenase
- Transketolase
- Transaldolase
Correct Answer: Glucose-6-phosphate dehydrogenase (G6PD)
Q31. Which cofactor is primarily used for reductive biosynthesis such as fatty acid synthesis?
- NADH
- FADH2
- NADPH
- ATP
Correct Answer: NADPH
Q32. Which amino sugar commonly appears in glycosaminoglycans and glycoproteins?
- Glucosamine (N-acetylglucosamine)
- Ribose
- Glucose-6-phosphate
- Sorbitol
Correct Answer: Glucosamine (N-acetylglucosamine)
Q33. Which transporter mediates Na+-dependent glucose uptake across the intestinal brush border?
- GLUT2
- GLUT5
- SGLT1
- SGLT2
Correct Answer: SGLT1
Q34. Glycosylation of proteins refers to:
- Attachment of phosphate groups to proteins
- Attachment of lipid chains to proteins
- Attachment of carbohydrate chains to proteins or lipids
- Proteolytic cleavage of peptides
Correct Answer: Attachment of carbohydrate chains to proteins or lipids
Q35. Which disaccharide is composed of glucose linked to fructose?
- Lactose
- Sucrose
- Maltose
- Cellobiose
Correct Answer: Sucrose
Q36. Clinical glucose meters commonly use which enzyme principle for measuring blood glucose?
- Hexokinase with spectrophotometric NADH measurement
- Glucose oxidase producing hydrogen peroxide detected electrochemically
- Lactate dehydrogenase producing lactate measured colorimetrically
- Glycogen phosphorylase assay
Correct Answer: Glucose oxidase producing hydrogen peroxide detected electrochemically
Q37. What is the net yield of ATP molecules from glycolysis per mole of glucose under anaerobic conditions?
- 0 ATP
- 2 ATP
- 4 ATP
- 36 ATP
Correct Answer: 2 ATP
Q38. Which enzyme is the key regulatory and rate-limiting step in glycolysis?
- Hexokinase
- Phosphofructokinase-1 (PFK-1)
- Pyruvate kinase
- Aldolase
Correct Answer: Phosphofructokinase-1 (PFK-1)
Q39. Most naturally occurring monosaccharides have which stereochemical configuration?
- L-configuration
- D-configuration
- R-configuration at every chiral center
- S-configuration
Correct Answer: D-configuration
Q40. Which activated sugar donor participates in glucuronidation during phase II drug metabolism?
- UDP-glucuronic acid
- UDP-galactose
- GTP-glucose
- ATP-glucose
Correct Answer: UDP-glucuronic acid
Q41. The phosphorylation of glucose to glucose-6-phosphate in peripheral tissues is catalyzed primarily by which enzyme?
- Glucokinase
- Hexokinase
- Phosphoglucose isomerase
- Glycogen synthase
Correct Answer: Hexokinase
Q42. Glycoproteins on the cell surface are chiefly involved in:
- Energy storage
- Cell-cell recognition and signaling
- DNA replication
- Lipid oxidation
Correct Answer: Cell-cell recognition and signaling
Q43. Which disaccharide consists of two glucose units joined by an alpha-1,4 bond?
- Cellobiose
- Maltose
- Sucrose
- Lactose
Correct Answer: Maltose
Q44. Rapidly dividing cells often increase flux through which pathway to supply NADPH and ribose?
- Glycolysis
- Pentose phosphate pathway
- Citric acid cycle
- Urea cycle
Correct Answer: Pentose phosphate pathway
Q45. Which glycosaminoglycan is abundant in synovial fluid and contributes to joint lubrication?
- Chondroitin sulfate
- Heparin
- Hyaluronic acid (hyaluronan)
- Keratansulfate
Correct Answer: Hyaluronic acid (hyaluronan)
Q46. Mutarotation refers to which phenomenon in carbohydrate chemistry?
- Cleavage of glycosidic bonds by acid
- Interconversion between alpha and beta anomers changing optical rotation
- Conversion of aldoses to ketoses by isomerase
- Oxidation of aldehyde group to acid
Correct Answer: Interconversion between alpha and beta anomers changing optical rotation
Q47. Hereditary fructose intolerance is caused by deficiency of which enzyme leading to accumulation of fructose-1-phosphate?
- Fructokinase
- Aldolase B
- Sorbitol dehydrogenase
- Hexokinase
Correct Answer: Aldolase B
Q48. Which hepatic enzyme family catalyzes glucuronidation of drugs, enhancing water solubility for excretion?
- CYP450 oxidases
- UDP-glucuronosyltransferases (UGTs)
- Glutathione S-transferases
- N-acetyltransferases
Correct Answer: UDP-glucuronosyltransferases (UGTs)
Q49. Which polysaccharide is highly branched with alpha-1,4 chains and alpha-1,6 branch points and serves as rapid-release glucose reserve in animals?
- Amylose
- Cellulose
- Glycogen
- Chitin
Correct Answer: Glycogen
Q50. Approximately how many ATP molecules are produced by complete aerobic oxidation of one molecule of glucose in typical eukaryotic cells?
- 2 ATP
- 6 ATP
- 30–32 ATP
- 100 ATP
Correct Answer: 30–32 ATP
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