Role of digestive enzymes MCQs With Answer

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Role of digestive enzymes MCQs With Answer

Understanding the role of digestive enzymes is essential for B.Pharm students preparing for pharmacology, biochemistry, and therapeutics. This concise, keyword-rich introduction covers digestive enzymes, enzyme classes (proteases, lipases, amylases), zymogen activation, pH optima, clinical relevance such as enzyme replacement therapy, pancreatitis, cystic fibrosis, and pharmacological inhibitors. Familiarity with enzyme kinetics, absorption, and diagnostic assays strengthens clinical decision-making and drug design. These MCQs emphasize mechanisms, regulation, drug interactions, and lab interpretation to build strong conceptual and applied knowledge for exams and practice. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which enzyme is primarily responsible for protein digestion in the stomach?

  • Trypsin
  • Pepsin
  • Pancreatic protease
  • Brush border peptidase

Correct Answer: Pepsin

Q2. Which pancreatic enzyme is most important for carbohydrate digestion?

  • Lipase
  • Amylase
  • Protease
  • Enterokinase

Correct Answer: Amylase

Q3. Zymogens are:

  • Active enzymes secreted by glands
  • Inactive enzyme precursors requiring activation
  • Coenzymes necessary for enzyme activity
  • Enzyme inhibitors produced by the liver

Correct Answer: Inactive enzyme precursors requiring activation

Q4. Enteropeptidase (enterokinase) activates which zymogen in the duodenum?

  • Pepsinogen
  • Trypsinogen
  • Proelastase
  • Prolipase

Correct Answer: Trypsinogen

Q5. Which enzyme class breaks triglycerides into monoglycerides and free fatty acids?

  • Proteases
  • Amylases
  • Lipases
  • Carboxypeptidases

Correct Answer: Lipases

Q6. Which pancreatic enzyme requires colipase and bile salts for efficient activity in the intestinal lumen?

  • Pancreatic amylase
  • Pancreatic lipase
  • Trypsin
  • Chymotrypsin

Correct Answer: Pancreatic lipase

Q7. Lactase deficiency leads to malabsorption of which sugar?

  • Sucrose
  • Lactose
  • Maltose
  • Fructose

Correct Answer: Lactose

Q8. Which enzyme is secreted by chief cells in the stomach?

  • Pepsinogen
  • Gastrin
  • Enterokinase
  • Secretin

Correct Answer: Pepsinogen

Q9. The optimal pH for pepsin activity is approximately:

  • 7.4
  • 8.5
  • 2.0
  • 5.5

Correct Answer: 2.0

Q10. Which enzyme converts trypsinogen to trypsin?

  • Pepsin
  • Enteropeptidase
  • Carboxypeptidase
  • Lipase

Correct Answer: Enteropeptidase

Q11. Chymotrypsinogen is activated by which enzyme?

  • Trypsin
  • Pepsin
  • Amylase
  • Lipase

Correct Answer: Trypsin

Q12. Which brush border enzyme is essential for final protein digestion into amino acids?

  • Sucrase
  • Lactase
  • Aminopeptidase
  • Pancreatic amylase

Correct Answer: Aminopeptidase

Q13. Orlistat reduces fat absorption by inhibiting which enzyme?

  • Pancreatic lipase
  • Pancreatic amylase
  • Trypsin
  • Brush border hydrolases

Correct Answer: Pancreatic lipase

Q14. Which enzyme deficiency is commonly measured in serum to diagnose pancreatitis?

  • Alkaline phosphatase
  • Aspartate transaminase
  • Amylase and lipase
  • Lactate dehydrogenase

Correct Answer: Amylase and lipase

Q15. The initial digestion of starch begins in the mouth by which enzyme?

  • Lingual lipase
  • Salivary amylase (ptyalin)
  • Pancreatic amylase
  • Brush border maltase

Correct Answer: Salivary amylase (ptyalin)

Q16. Which cofactor is essential for pancreatic lipase activity in forming enzyme–lipid interface?

  • Vitamin B12
  • Calcium ions
  • Colipase
  • Magnesium ions

Correct Answer: Colipase

Q17. Aprotinin is a clinical inhibitor of which type of enzyme?

  • Proteases
  • Amylases
  • Lipases
  • Oxidases

Correct Answer: Proteases

Q18. Which enzyme hydrolyzes peptide bonds at aromatic amino acids preferentially?

  • Trypsin
  • Chymotrypsin
  • Carboxypeptidase A
  • Aminopeptidase

Correct Answer: Chymotrypsin

Q19. Endopeptidases differ from exopeptidases because endopeptidases:

  • Remove terminal amino acids
  • Hydrolyze internal peptide bonds
  • Require bile salts
  • Act only in the stomach

Correct Answer: Hydrolyze internal peptide bonds

Q20. Which enzyme deficiency causes congenital sucrase-isomaltase deficiency?

  • Lactase deficiency
  • Sucrase-isomaltase deficiency
  • Maltase deficiency
  • Sucrose synthase deficiency

Correct Answer: Sucrase-isomaltase deficiency

Q21. Pancreatic enzyme replacement therapy is commonly used in which condition?

  • Peptic ulcer disease
  • Cystic fibrosis with exocrine pancreatic insufficiency

Correct Answer: Cystic fibrosis with exocrine pancreatic insufficiency

Q22. Which of the following brush border enzymes splits maltose to glucose?

  • Lactase
  • Sucrase
  • Maltase
  • Isomaltase

Correct Answer: Maltase

Q23. What is the primary effect of acidic pH on pancreatic enzymes in the duodenum if not neutralized?

  • Activation of zymogens
  • Denaturation and loss of activity
  • Increased absorption of amino acids
  • Enhanced lipase activity

Correct Answer: Denaturation and loss of activity

Q24. Secretin mainly stimulates the pancreas to secrete:

  • Enzyme-rich, acidic fluid
  • Bile
  • Bicarbonate-rich fluid to neutralize acid
  • Mucus for protection

Correct Answer: Bicarbonate-rich fluid to neutralize acid

Q25. Which enzyme cleaves peptide bonds adjacent to basic amino acids (lysine, arginine)?

  • Trypsin
  • Chymotrypsin
  • Elastase
  • Carboxypeptidase B

Correct Answer: Trypsin

Q26. Brush border disaccharidases are located on:

  • Lumen of pancreatic acini
  • Microvilli of enterocytes
  • Gastric pits

Correct Answer: Microvilli of enterocytes

Q27. Which technique measures enzyme activity by monitoring substrate conversion per unit time?

  • Immunoassay for enzyme concentration
  • Enzyme kinetic assay (activity assay)
  • Western blot
  • Histopathology

Correct Answer: Enzyme kinetic assay (activity assay)

Q28. Which inhibitor type binds to the active site and is overcome by increasing substrate concentration?

  • Non-competitive inhibitor
  • Uncompetitive inhibitor
  • Competitive inhibitor
  • Allosteric inhibitor

Correct Answer: Competitive inhibitor

Q29. In cystic fibrosis, reduced pancreatic enzyme secretion primarily impairs absorption of:

  • Water-soluble vitamins
  • Fat-soluble vitamins (A, D, E, K)
  • Vitamin B12 only
  • Iron

Correct Answer: Fat-soluble vitamins (A, D, E, K)

Q30. Which enzyme is mainly responsible for initiating triglyceride digestion in the stomach in neonates?

  • Pancreatic lipase
  • Gastric lipase
  • Lingual lipase
  • Hepatic lipase

Correct Answer: Gastric lipase

Q31. Which vitamin is required for carboxylase enzymes rather than classical digestive enzymes?

  • Vitamin C
  • Vitamin K
  • Vitamin B1 (thiamine)
  • Vitamin B3 (niacin)

Correct Answer: Vitamin K

Q32. An increase in Km for an enzyme indicates:

  • Higher affinity for substrate
  • Lower affinity for substrate
  • Increased Vmax
  • Unchanged affinity

Correct Answer: Lower affinity for substrate

Q33. Which pancreatic protease is an exopeptidase that removes C-terminal amino acids?

  • Trypsin
  • Carboxypeptidase
  • Chymotrypsin
  • Aminopeptidase

Correct Answer: Carboxypeptidase

Q34. Which intestinal hormone primarily stimulates pancreatic enzyme secretion?

  • Secretin
  • Gastrin
  • Cholecystokinin (CCK)
  • Somatostatin

Correct Answer: Cholecystokinin (CCK)

Q35. Pancreatic insufficiency leads to steatorrhea because of impaired:

  • Carbohydrate digestion
  • Fat digestion and absorption
  • Protein catabolism in liver
  • Gastric acid secretion

Correct Answer: Fat digestion and absorption

Q36. Which enzyme hydrolyzes dietary nucleic acids in the gut?

  • Nucleases
  • Lipases
  • Proteases
  • Amylases

Correct Answer: Nucleases

Q37. Which condition increases serum alkaline phosphatase but is not a primary digestive enzyme issue?

  • Cholestasis (biliary obstruction)
  • Lactase deficiency
  • Pancreatitis
  • Gastritis

Correct Answer: Cholestasis (biliary obstruction)

Q38. Which of the following affects enzyme activity by altering tertiary structure and causing denaturation?

  • Physiological substrate concentration
  • Extreme temperature and pH
  • Presence of cofactors at normal levels
  • Optimal ionic strength

Correct Answer: Extreme temperature and pH

Q39. Which protease inhibitor is used clinically to reduce pancreatic enzyme activity in severe pancreatitis?

  • Trypsin inhibitor (e.g., aprotinin)
  • Orlistat
  • ACE inhibitor
  • Statins

Correct Answer: Trypsin inhibitor (e.g., aprotinin)

Q40. Brush border enzyme deficiency causing lactose intolerance typically results from decreased activity of:

  • Sucrase-isomaltase
  • Lactase-phlorizin hydrolase
  • Maltase-glucoamylase
  • Peptidases

Correct Answer: Lactase-phlorizin hydrolase

Q41. Which of the following is a clinical use of digestive enzyme assays?

  • Diagnosing myocardial infarction only
  • Assessing exocrine pancreatic function and pancreatitis
  • Measuring neurotransmitter levels
  • Monitoring renal filtration rate

Correct Answer: Assessing exocrine pancreatic function and pancreatitis

Q42. Which enzyme class requires a metal ion cofactor in many cases (metalloenzymes)?

  • Serine proteases exclusively
  • Metalloproteases
  • All lipases
  • All amylases

Correct Answer: Metalloproteases

Q43. Which pharmacological agent reduces gastric acidity and may indirectly affect pepsin activity?

  • Proton pump inhibitors (PPIs)
  • Pancrelipase
  • Lactase supplements
  • Orlistat

Correct Answer: Proton pump inhibitors (PPIs)

Q44. Which digestive enzyme is primarily responsible for collagen degradation in the stomach or pancreas?

  • Elastase
  • Collagenase (matrix metalloproteinase family)
  • Amylase
  • Sucrase

Correct Answer: Collagenase (matrix metalloproteinase family)

Q45. Which diagnostic pattern suggests chronic pancreatitis with exocrine insufficiency?

  • Normal fecal elastase levels
  • Low fecal elastase and steatorrhea
  • High lactase activity
  • Elevated gastric pH only

Correct Answer: Low fecal elastase and steatorrhea

Q46. Activation of pepsinogen to pepsin requires:

  • Bile salts
  • Acidic environment (HCl)
  • Enterokinase
  • Colipase

Correct Answer: Acidic environment (HCl)

Q47. Which dietary factor enhances pancreatic enzyme secretion via CCK release?

  • High-carbohydrate meal only
  • High-fat and high-protein meal
  • Pure water ingestion
  • Fasting state

Correct Answer: High-fat and high-protein meal

Q48. Which lab test specifically assesses small intestinal disaccharidase activity?

  • Serum amylase
  • Fecal elastase
  • Small intestinal biopsy with enzyme assay
  • Serum lipase

Correct Answer: Small intestinal biopsy with enzyme assay

Q49. Which statement about pancreatic amylase and salivary amylase is correct?

  • Both are inactivated by stomach acid before reaching intestine
  • Salivary amylase continues to act in stomach acidic pH long-term
  • Pancreatic amylase completes starch digestion after neutralization in duodenum
  • Neither contributes to carbohydrate digestion

Correct Answer: Pancreatic amylase completes starch digestion after neutralization in duodenum

Q50. Which therapeutic strategy is used to manage exocrine pancreatic insufficiency?

  • High-dose proton pump inhibitors only
  • Pancreatic enzyme replacement therapy with meals
  • Oral statins to improve enzyme secretion
  • Administering bile acid sequestrants

Correct Answer: Pancreatic enzyme replacement therapy with meals

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