The NEET (National Eligibility cum Entrance Test) is a gateway to some of the most prestigious medical colleges in India. Biology plays a critical role in this exam, contributing to half of the total score. Among the topics covered in Biology, the Human Digestive System is a core concept that every aspiring doctor must understand thoroughly. The digestive system is not only a fundamental part of human physiology but also frequently appears in NEET questions, making it essential for you to master.

Cracking NEET Biology: Mastering the Human Digestive System

Why Are These Questions Important for the NEET Biology Exam?

Understanding the Human Digestive System is crucial because it integrates knowledge from various biological processes, including enzymatic reactions, absorption, and hormonal regulation. These MCQs help reinforce these concepts, ensuring that you are well-prepared for any question that might come your way in the NEET exam. Moreover, these questions will test your ability to apply what you've learned, a key skill needed for success in NEET.

MCQs on Human Digestive System

1. Which of the following is the primary function of the large intestine?

• a) Digestion of proteins
• b) Absorption of water and electrolytes
• c) Secretion of digestive enzymes
• d) Storage of bile

Answer: b) Absorption of water and electrolytes

• Explanation: The large intestine's main role is to absorb water and electrolytes from the indigestible food matter, forming solid waste for excretion.

2. What is the role of bile in digestion?

• a) Breaking down carbohydrates
• b) Neutralizing stomach acid
• c) Emulsifying fats
• d) Digesting proteins

Answer: c) Emulsifying fats

• Explanation: Bile, produced by the liver and stored in the gallbladder, emulsifies fats, breaking them down into smaller droplets, which aids in fat digestion by enzymes like lipase.

3. Which enzyme is responsible for the digestion of starch in the mouth?

• a) Pepsin
• b) Lipase
• c) Amylase
• d) Trypsin

Answer: c) Amylase

• Explanation: Salivary amylase, present in saliva, begins the digestion of starch in the mouth by breaking it down into maltose.

4. Where is the majority of nutrient absorption in the digestive system?

• a) Stomach
• b) Large intestine
• c) Small intestine
• d) Esophagus

Answer: c) Small intestine

• Explanation: The small intestine, particularly the jejunum and ileum, is the primary site for nutrient absorption due to its extensive surface area provided by villi and microvilli.

5. What triggers the release of gastrin in the stomach?

• a) Presence of bile
• b) Low pH
• c) Presence of food
• d) High fat content

Answer: c) Presence of food

• Explanation: The presence of food, especially proteins, in the stomach stimulates the release of gastrin, which in turn increases the secretion of gastric acid.

6. Which part of the digestive system is primarily responsible for water reabsorption?

• a) Small intestine
• b) Large intestine
• c) Stomach
• d) Pancreas

Answer: b) Large intestine

• Explanation: The large intestine reabsorbs water from the indigestible food matter, preventing dehydration and forming solid stool.

7. Which hormone stimulates the pancreas to release bicarbonate into the small intestine?

• a) Gastrin
• b) Secretin
• c) Cholecystokinin (CCK)
• d) Insulin

Answer: b) Secretin

• Explanation: Secretin is released in response to acidic chyme entering the small intestine and prompts the pancreas to release bicarbonate to neutralize the acid.

8. Pepsinogen is converted to pepsin in the stomach. What activates this conversion?

• a) Presence of bile
• b) Presence of food
• c) Hydrochloric acid (HCl)
• d) Trypsin

Answer: c) Hydrochloric acid (HCl)

• Explanation: Hydrochloric acid in the stomach activates pepsinogen into pepsin, an enzyme crucial for the digestion of proteins.

9. Which of the following is NOT a function of the liver?

• a) Detoxification
• b) Production of bile
• c) Storage of glycogen
• d) Production of insulin

Answer: d) Production of insulin

• Explanation: Insulin is produced by the pancreas, not the liver. The liver's functions include detoxification, bile production, and glycogen storage.

10. Which part of the digestive system contains villi?

• a) Stomach
• b) Small intestine
• c) Large intestine
• d) Esophagus

Answer: b) Small intestine

• Explanation: Villi are finger-like projections in the small intestine that increase surface area for nutrient absorption.

11. The acidic environment in the stomach is primarily due to which of the following?

• a) Bile secretion
• b) HCl secretion
• c) Pepsin activity
• d) Amylase secretion

Answer: b) HCl secretion

• Explanation: The stomach secretes hydrochloric acid (HCl), creating an acidic environment necessary for activating digestive enzymes like pepsin.

12. Which organ is responsible for the production of most digestive enzymes?

• a) Stomach
• b) Liver
• c) Pancreas
• d) Gallbladder

Answer: c) Pancreas

• Explanation: The pancreas produces a variety of digestive enzymes, including amylase, lipase, and proteases, which are released into the small intestine.

13. Which of the following is NOT absorbed directly into the bloodstream from the small intestine?

• a) Glucose
• b) Amino acids
• c) Fatty acids
• d) Water

Answer: c) Fatty acids

• Explanation: Fatty acids are absorbed into the lymphatic system via lacteals before entering the bloodstream.

14. What is the primary function of the stomach?

• a) Absorption of nutrients
• b) Digestion of carbohydrates
• c) Protein digestion and food storage
• d) Excretion of waste

Answer: c) Protein digestion and food storage

• Explanation: The stomach's main roles are to store food and initiate protein digestion with the help of pepsin and HCl.

15. Where does the majority of chemical digestion occur?

• a) Mouth
• b) Stomach
• c) Small intestine
• d) Large intestine

Answer: c) Small intestine

• Explanation: Most chemical digestion occurs in the small intestine, where enzymes from the pancreas and bile from the liver act on the chyme.

16. Which of the following enzymes breaks down proteins into peptides?

• a) Amylase
• b) Lipase
• c) Pepsin
• d) Lactase

Answer: c) Pepsin

• Explanation: Pepsin is an enzyme in the stomach that breaks down proteins into smaller peptides.

17. The hormone cholecystokinin (CCK) has which of the following effects?

• a) Inhibits stomach motility
• b) Stimulates bile release from the gallbladder
• c) Increases HCl production
• d) Decreases blood glucose levels

Answer: b) Stimulates bile release from the gallbladder

• Explanation: Cholecystokinin (CCK) stimulates the gallbladder to release bile into the small intestine to aid in fat digestion.

18. What is the role of the ileocecal valve?

• a) Regulates the flow of chyme from the stomach to the small intestine
• b) Prevents the backflow of waste from the large intestine to the small intestine
• c) Controls the release of bile
• d) Opens the pancreatic duct

Answer: b) Prevents the backflow of waste from the large intestine to the small intestine

• Explanation: The ileocecal valve prevents the backflow of fecal material from the large intestine into the small intestine.

19. Which vitamin is synthesized by bacteria in the large intestine?

• a) Vitamin C
• b) Vitamin K
• c) Vitamin D
• d) Vitamin A

Answer: b) Vitamin K

• Explanation: Vitamin K is synthesized by gut bacteria in the large intestine and plays a crucial role in blood clotting.

20. Which of the following is the first part of the small intestine?

• a) Jejunum
• b) Ileum
• c) Duodenum
• d) Cecum

Answer: c) Duodenum

• Explanation: The duodenum is the first part of the small intestine, where a significant portion of chemical digestion occurs.

21. Which digestive enzyme is secreted in an inactive form to prevent self-digestion of the pancreas?

• a) Amylase
• b) Lipase
• c) Trypsinogen
• d) Lactase

Answer: c) Trypsinogen

• Explanation: Trypsinogen is secreted in an inactive form and is activated in the small intestine to prevent the pancreas from digesting itself.

22. Where does the majority of fat digestion occur?

• a) Mouth
• b) Stomach
• c) Small intestine
• d) Large intestine

Answer: c) Small intestine

• Explanation: Fat digestion occurs primarily in the small intestine, with the help of bile and pancreatic lipase.

23. Which of the following is NOT a component of gastric juice?

• a) Pepsinogen
• b) Hydrochloric acid (HCl)
• c) Amylase
• d) Mucus

Answer: c) Amylase

• Explanation: Amylase is present in saliva and is not a component of gastric juice. Gastric juice contains pepsinogen, HCl, and mucus.

24. Which of the following structures is responsible for the absorption of fats in the small intestine?

• a) Villi
• b) Microvilli
• c) Lacteals
• d) Goblet cells

Answer: c) Lacteals

• Explanation: Lacteals are lymphatic vessels in the villi of the small intestine responsible for absorbing fats and transporting them to the bloodstream.

25. The intrinsic factor, essential for the absorption of vitamin B12, is secreted by which cells?

• a) Chief cells
• b) Parietal cells
• c) Goblet cells
• d) Enterocytes

Answer: b) Parietal cells

• Explanation: Parietal cells in the stomach secrete the intrinsic factor, which is essential for vitamin B12 absorption in the small intestine.

26. Which of the following is a common symptom of vitamin K deficiency?

• a) Anemia
• b) Bleeding disorders
• c) Scurvy
• d) Night blindness

Answer: b) Bleeding disorders

• Explanation: Vitamin K is essential for blood clotting, and its deficiency can lead to bleeding disorders.

27. What role does the hormone ghrelin play in digestion?

• a) Stimulates bile secretion
• b) Suppresses appetite
• c) Increases appetite
• d) Lowers blood glucose levels

Answer: c) Increases appetite

• Explanation: Ghrelin is a hormone produced by the stomach that stimulates appetite and increases food intake.

28. Which of the following nutrients begins digestion in the stomach?

• a) Carbohydrates
• b) Proteins
• c) Fats
• d) Vitamins

Answer: b) Proteins

• Explanation: Protein digestion begins in the stomach with the action of pepsin and hydrochloric acid.

29. Which of the following is a protective mechanism that prevents self-digestion in the stomach?

• a) Mucus secretion
• b) Low pH
• c) Enzyme secretion
• d) Bile production

Answer: a) Mucus secretion

• Explanation: The stomach is lined with mucus, which protects it from the corrosive effects of hydrochloric acid and digestive enzymes.

30. Which of the following processes is responsible for moving food through the digestive tract?

• a) Peristalsis
• b) Segmentation
• c) Digestion
• d) Absorption

Answer: a) Peristalsis

• Explanation: Peristalsis is the rhythmic contraction of muscles in the digestive tract that moves food from the esophagus to the stomach and through the intestines.

31. The enzyme lactase is responsible for breaking down which of the following?

• a) Sucrose
• b) Lactose
• c) Glucose
• d) Maltose

Answer: b) Lactose

• Explanation: Lactase breaks down lactose, a sugar found in milk, into glucose and galactose.

32. Which of the following is the primary site for the digestion of proteins?

• a) Mouth
• b) Stomach
• c) Small intestine
• d) Large intestine

Answer: c) Small intestine

• Explanation: While protein digestion begins in the stomach, the majority occurs in the small intestine with the action of pancreatic enzymes.

33. Which of the following best describes the role of hydrochloric acid in the stomach?

• a) Digestion of carbohydrates
• b) Activation of digestive enzymes
• c) Emulsification of fats
• d) Absorption of nutrients

Answer: b) Activation of digestive enzymes

• Explanation: Hydrochloric acid in the stomach lowers the pH, which activates digestive enzymes like pepsin for protein digestion.

34. Which structure prevents food from entering the nasal passages during swallowing?

• a) Epiglottis
• b) Uvula
• c) Glottis
• d) Larynx

Answer: b) Uvula

• Explanation: The uvula helps to close off the nasopharynx during swallowing, preventing food from entering the nasal passages.

35. Which of the following is the main function of the pyloric sphincter?

• a) Regulate the passage of food from the stomach to the small intestine
• b) Prevent the backflow of bile
• c) Release digestive enzymes
• d) Absorb nutrients

Answer: a) Regulate the passage of food from the stomach to the small intestine

• Explanation: The pyloric sphincter controls the passage of chyme from the stomach to the duodenum of the small intestine.

36. Which of the following organs is NOT involved in the production or storage of bile?

• a) Liver
• b) Gallbladder
• c) Pancreas
• d) Small intestine

Answer: c) Pancreas

• Explanation: The pancreas produces digestive enzymes and bicarbonate but is not involved in the production or storage of bile.

37. Which of the following is a function of the hormone gastrin?

• a) Inhibit stomach acid production
• b) Stimulate stomach acid production
• c) Increase bile secretion
• d) Promote insulin release

Answer: b) Stimulate stomach acid production

• Explanation: Gastrin is a hormone that stimulates the production of gastric acid in the stomach.

38. Where are Peyer’s patches found?

• a) Stomach
• b) Small intestine
• c) Large intestine
• d) Esophagus

Answer: b) Small intestine

• Explanation: Peyer's patches are lymphoid tissues located in the small intestine, particularly in the ileum, and play a role in immune surveillance.

39. What is the main function of the gallbladder?

• a) Production of bile
• b) Storage and concentration of bile
• c) Secretion of digestive enzymes
• d) Absorption of fats

Answer: b) Storage and concentration of bile

• Explanation: The gallbladder stores and concentrates bile produced by the liver, releasing it into the small intestine when needed.

40. Which of the following structures increases the surface area for absorption in the small intestine?

• a) Rugae
• b) Villi
• c) Plicae circulares
• d) Microvilli

Answer: d) Microvilli

• Explanation: Microvilli are tiny projections on the surface of epithelial cells in the small intestine that significantly increase the surface area for absorption.

41. Which part of the digestive system is primarily responsible for the absorption of water?

• a) Stomach
• b) Small intestine
• c) Large intestine
• d) Esophagus

Answer: c) Large intestine

• Explanation: The large intestine absorbs water from indigestible food residues, forming solid waste.

42. Which of the following nutrients is absorbed directly into the bloodstream from the small intestine?

• a) Glucose
• b) Fatty acids
• c) Amino acids
• d) Both a and c

Answer: d) Both a and c

• Explanation: Both glucose and amino acids are absorbed directly into the bloodstream from the small intestine.

43. The liver converts excess glucose into which of the following for storage?

• a) Glycogen
• b) Starch
• c) Fat
• d) Protein

Answer: a) Glycogen

• Explanation: The liver converts excess glucose into glycogen, which is stored in the liver and muscles for later use.

44. Which of the following enzymes is involved in the digestion of fats?

• a) Amylase
• b) Lipase
• c) Pepsin
• d) Trypsin

Answer: b) Lipase

• Explanation: Lipase is an enzyme that breaks down fats into fatty acids and glycerol.

45. Which structure prevents the backflow of stomach contents into the esophagus?

• a) Pyloric sphincter
• b) Ileocecal valve
• c) Lower esophageal sphincter (LES)
• d) Epiglottis

Answer: c) Lower esophageal sphincter (LES)

• Explanation: The lower esophageal sphincter (LES) prevents the backflow of acidic stomach contents into the esophagus, protecting it from damage.

46. Which of the following nutrients begins digestion in the mouth?

• a) Proteins
• b) Fats
• c) Carbohydrates
• d) Vitamins

Answer: c) Carbohydrates

• Explanation: Carbohydrate digestion begins in the mouth with the action of salivary amylase.

47. What is the primary function of the large intestine?

• a) Digestion of proteins
• b) Absorption of nutrients
• c) Absorption of water
• d) Breakdown of fats

Answer: c) Absorption of water

• Explanation: The large intestine primarily absorbs water and electrolytes, forming solid feces.

48. Which of the following is NOT a function of the stomach?

• a) Protein digestion
• b) Absorption of glucose
• c) Secretion of acid
• d) Food storage

Answer: b) Absorption of glucose

• Explanation: The stomach does not absorb glucose; its primary functions are protein digestion, acid secretion, and food storage.

49. Which of the following cells secrete hydrochloric acid in the stomach?

• a) Chief cells
• b) Parietal cells
• c) Goblet cells
• d) Enterocytes

Answer: b) Parietal cells

• Explanation: Parietal cells in the stomach lining secrete hydrochloric acid, which aids in digestion and creates an acidic environment.

50. Which of the following hormones is released in response to the presence of fatty acids in the small intestine?

• a) Gastrin
• b) Secretin
• c) Cholecystokinin (CCK)
• d) Insulin

Answer: c) Cholecystokinin (CCK)

• Explanation: Cholecystokinin (CCK) is released in response to fatty acids in the small intestine and stimulates the release of bile and pancreatic enzymes.

Conclusion

Mastering the Human Digestive System is crucial for your success in NEET Biology. These MCQs provide a comprehensive review of the topic, helping you to reinforce your knowledge and prepare for the exam. Remember, understanding the concepts behind these questions is key to applying your knowledge in different contexts during the exam.

Thank you for reading, and best of luck with your NEET preparations!

Regards,🎉

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