Free Digestion MCQs with Answers
680 Digestion MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The human digestive system covers the organs from mouth to anus, the movement of food, and the mechanical and chemical breakdown of carbohydrates, proteins and fats. It also includes the roles of digestive enzymes, bile, absorption through intestinal villi, and the assimilation of nutrients by body cells.
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Read the Digestion notesFree MDCAT chapter notes with key terms680 questions · page 3 of 34
- A. hydrochloric acid
- B. bicarbonate present in the pancreatic juice and bile
- C. pepsin
- D. salivary amylase
Explanation: Pancreatic bicarbonate raises the pH to around 8, the alkaline range in which pancreatic and intestinal enzymes work.
Correct answer: bicarbonate present in the pancreatic juice and bile- A. chyme
- B. bolus
- C. faeces
- D. bile
Explanation: Churning mixes food with gastric juice to form chyme, which is released in small amounts into the duodenum.
Correct answer: chyme- A. chyme
- B. plaque
- C. calculus
- D. bolus
Explanation: The tongue shapes moistened, chewed food into a slippery bolus sized for swallowing.
Correct answer: bolus- A. lipase
- B. trypsin
- C. maltase
- D. pepsin
Explanation: Maltase is one of the intestinal disaccharidases that finish carbohydrate digestion, alongside sucrase and lactase.
Correct answer: maltase- A. the villi of the small intestine
- B. bacteria living in the large intestine
- C. the pancreas
- D. the gall bladder
Explanation: The resident flora of the colon manufacture vitamin K and some B vitamins, which are absorbed there, one reason the gut microbiome…
Correct answer: bacteria living in the large intestine- A. defecation
- B. excretion
- C. secretion
- D. absorption
Explanation: Defecation, or egestion, removes material that never entered the body's tissues.
Correct answer: defecation- A. find it toxic
- B. digest it before it reaches the stomach
- C. absorb it without digestion
- D. lack the enzyme cellulase
Explanation: The beta glycosidic bonds of cellulose need cellulase, which human cells do not produce, so it passes through as fibre.
Correct answer: lack the enzyme cellulase- A. ulcer
- B. hernia
- C. appendicitis
- D. cholera
Explanation: The vermiform appendix can become infected and swollen, producing pain in the lower right abdomen, and may need surgical removal.
Correct answer: appendicitis49. Pepsin digests
- A. Carbohydrates
- B. Proteins
- C. Fats
- D. Nucleic acids
Explanation: Pepsin is a protease that digests proteins into peptides in the acidic environment of the stomach.
Correct answer: Proteins- A. Gall bladder
- B. Liver
- C. Pancreas
- D. Stomach
Explanation: Bile is produced by the liver, stored in the gall bladder, and released into the duodenum.
Correct answer: Liver- A. Digest fats enzymatically
- B. Emulsify fats
- C. Absorb fatty acids
- D. Produce lipase
Explanation: Bile salts emulsify fats, breaking large fat droplets into smaller ones to increase surface area for lipase action.
Correct answer: Emulsify fats- A. Stomach
- B. Duodenum
- C. Ileum
- D. Colon
Explanation: Most nutrient absorption occurs in the ileum (small intestine), which has villi and microvilli for maximum surface area.
Correct answer: Ileum- A. HCl
- B. Enterokinase/Enteropeptidase
- C. Pepsin
- D. Bile
Explanation: Enterokinase (enteropeptidase) from intestinal brush border activates trypsinogen to trypsin, which then activates other pancreatic enzymes.
Correct answer: Enterokinase/Enteropeptidase- A. Diabetes
- B. Lactose intolerance
- C. Celiac disease
- D. Pernicious anemia
Explanation: Lactase deficiency leads to lactose intolerance, causing bloating, gas, and diarrhea when dairy is consumed.
Correct answer: Lactose intolerance- A. Iron
- B. Vitamin B12
- C. Calcium
- D. Vitamin D
Explanation: Intrinsic factor from gastric parietal cells binds vitamin B12 for absorption in the ileum; its deficiency causes pernicious anemia.
Correct answer: Vitamin B12- A. Liver to heart
- B. Intestines to liver
- C. Liver to kidneys
- D. Spleen to liver
Explanation: The hepatic portal vein carries nutrient-rich blood from the digestive organs to the liver for processing.
Correct answer: Intestines to liver- A. HCl
- B. Bicarbonate
- C. Pepsin
- D. Bile
Explanation: Sodium bicarbonate in pancreatic juice neutralizes acidic chyme from the stomach, creating optimal pH for enzymes.
Correct answer: Bicarbonate- A. Liver
- B. Intestinal epithelial cells
- C. Blood
- D. Adipose tissue
Explanation: Chylomicrons (lipoprotein particles containing triglycerides) are formed in intestinal epithelial cells after fat absorption.
Correct answer: Intestinal epithelial cells- A. Amylase
- B. Pepsinogens
- C. Enterokinase
- D. Lipase
Explanation: Enterokinase from the duodenal lining converts trypsinogen into active trypsin, which then activates the other pancreatic proenzymes in…
Correct answer: Enterokinase- A. Left Lower Quadrant
- B. Right Upper Quadrant
- C. Right lower Quadrant
- D. Left Upper Quadrant
Explanation: The appendix is a narrow, finger-like projection from the caecum, which lies in the right lower quadrant of the abdomen.
Correct answer: Right lower Quadrant