NEET 2025 MCQ with Answer Explanation : “Digestion and Absorption”.

MCQ 51:
What role do bile salts play in fat digestion?

A) Emulsification of fats
B) Protein digestion
C) Carbohydrate absorption
D) Vitamin absorption

Answer: A) Emulsification of fats

Explanation: Bile salts emulsify fats, increasing their surface area for digestion by lipases.

MCQ 52:
Which structure prevents the reflux of stomach contents into the esophagus?

A) Pyloric sphincter
B) Cardiac sphincter
C) Ileocecal valve
D) Anal sphincter

Answer: B) Cardiac sphincter

Explanation: The cardiac sphincter (lower esophageal sphincter) prevents the backflow of stomach contents into the esophagus.

MCQ 53:
Which of the following is a function of saliva?

A) Absorbing nutrients
B) Activating enzymes
C) Digestion of proteins
D) Emulsifying fats

Answer: B) Activating enzymes

Explanation: Saliva contains enzymes like amylase that begin the digestion of carbohydrates.

MCQ 54:
What is the main function of the intestinal villi?

A) Secretion of enzymes
B) Absorption of nutrients
C) Emulsification of fats
D) Digestion of proteins

Answer: B) Absorption of nutrients

Explanation: Villi increase the surface area of the intestinal lining, enhancing nutrient absorption.

MCQ 55:
Which of the following nutrients is absorbed via passive diffusion?

A) Glucose
B) Water
C) Amino acids
D) Vitamins

Answer: B) Water

Explanation: Water is absorbed by passive diffusion through osmosis across the intestinal lining.

MCQ 56:
Which of the following enzymes is secreted by the pancreas?

A) Pepsin
B) Amylase
C) Lactase
D) Maltase

Answer: B) Amylase

Explanation: The pancreas secretes amylase, which is involved in carbohydrate digestion in the small intestine.

MCQ 57:
What is the primary function of the stomach?

A) Absorption of nutrients
B) Mechanical digestion and initial protein digestion
C) Emulsification of fats
D) Storage of bile

Answer: B) Mechanical digestion and initial protein digestion

Explanation: The stomach mechanically churns food and initiates protein digestion through gastric juices.

MCQ 58:
Which hormone stimulates the secretion of gastric acid?

A) Secretin
B) Gastrin
C) Cholecystokinin
D) Insulin

Answer: B) Gastrin

Explanation: Gastrin is released in response to food intake and stimulates the stomach to secrete gastric acid.

MCQ 59:
What is the function of the pyloric sphincter?

A) Prevents food from entering the stomach
B) Regulates the passage of chyme into the duodenum
C) Secretes digestive enzymes
D) Absorbs nutrients

Answer: B) Regulates the passage of chyme into the duodenum

Explanation: The pyloric sphincter controls the movement of partially digested food (chyme) from the stomach into the small intestine.

MCQ 60:
Which of the following is NOT a carbohydrate?

A) Glucose
B) Fructose
C) Sucrose
D) Glycogen
E) Cholesterol

Answer: E) Cholesterol

Explanation: Cholesterol is a lipid, not a carbohydrate; the others are all types of carbohydrates.