Human Physiology – Digestion and Absorption Quiz - ICSE Class 11 Biology

Free practice quiz: Human Physiology – Digestion and Absorption (ICSE Class 11 Biology). 45 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 11 Biology practice quiz has 45 multiple-choice questions on Human Physiology – Digestion and Absorption, and 45 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. Which enzyme, secreted by the stomach, is responsible for the initial breakdown of proteins into smaller polypeptides?

   1. Trypsin
   2. Pepsin
   3. Chymotrypsin
   4. Carboxypeptidase
   Show answer

   Answer: B. Pepsin

   Pepsin is the primary proteolytic enzyme in the stomach. It is secreted as an inactive zymogen, pepsinogen, which is activated by the acidic environment of the stomach. Pepsin breaks down proteins into smaller polypeptides.

2. Which vitamin is synthesized by the gut bacteria in the large intestine and absorbed by the host?

   1. Vitamin C
   2. Vitamin D
   3. Vitamin K
   4. Vitamin A
   Show answer

   Answer: C. Vitamin K

   Certain species of bacteria in the large intestine, such as E. coli, synthesize vitamin K. This vitamin is then absorbed by the host and plays a crucial role in blood clotting.

3. The initial enzymatic breakdown of carbohydrates begins in the:

   1. Stomach
   2. Mouth
   3. Small intestine
   4. Large intestine
   Show answer

   Answer: B. Mouth

   Saliva, produced in the mouth, contains salivary amylase (ptyalin), which begins the digestion of starch (a polysaccharide) into smaller polysaccharides and disaccharides.

4. The bacterial fermentation of undigested carbohydrates in the large intestine produces:

   1. Fatty acids and vitamins
   2. Amino acids and ammonia
   3. Ketone bodies and glucose
   4. Steroids and cholesterol
   Show answer

   Answer: A. Fatty acids and vitamins

   Bacteria in the colon ferment undigested carbohydrates, producing short-chain fatty acids (like acetate, propionate, and butyrate), which can be absorbed and used as energy by the host, and also synthesize some vitamins, such as vitamin K and several B vitamins.

5. Which of the following is NOT a function of the liver in digestion?

   1. Production of bile
   2. Synthesis of plasma proteins
   3. Detoxification of absorbed substances
   4. Secretion of digestive enzymes
   Show answer

   Answer: D. Secretion of digestive enzymes

   The liver's main digestive function is the production of bile, which aids in fat digestion and absorption. It also plays crucial roles in metabolism, detoxification of absorbed substances, and synthesis of plasma proteins. The secretion of major digestive enzymes is primarily a function of the pancreas and the small intestine.

More questions in this quiz

Answers and explanations are in the full quiz.

1. The hepatic portal vein carries nutrient-rich blood from the digestive organs directly to which organ for processing?
2. Which of the following is NOT a function of bile salts in the digestion of fats?
3. What is the primary role of the intrinsic factor, secreted by parietal cells of the stomach, in digestion and absorption?
4. Which hormone, released by the duodenum in response to acidic chyme, stimulates the pancreas to release bicarbonate-rich fluid?
5. The brush border enzymes, such as sucrase and lactase, are primarily located on the microvilli of which part of the digestive tract?
6. During absorption in the small intestine, which of the following nutrients is absorbed directly into the bloodstream without being re-esterified into triglycerides within the enterocytes?
7. The presence of which nutrient in the small intestine stimulates the release of cholecystokinin (CCK)?
8. What is the primary site for the absorption of water and electrolytes in the digestive system?
9. The cephalic phase of digestion is primarily initiated by:
10. Which hormone inhibits gastric emptying and stimulates the secretion of pancreatic enzymes and bile?
11. What is the role of mucus in the stomach?
12. Which of the following is a primary function of the small intestine's villi and microvilli?
13. The enzyme responsible for hydrolyzing triglycerides into fatty acids and glycerol is:
14. Which hormone, secreted by the stomach, stimulates gastric acid secretion and gastric motility?
15. The absorption of which nutrient is significantly hindered in the absence of bile salts?
16. Which of the following is a disaccharide that is digested by the enzyme sucrase?
17. Which component of the gastric juice is responsible for killing ingested microorganisms and providing an acidic environment for pepsin activation?
18. The synthesis of chylomicrons occurs in the enterocytes for the transport of:
19. Which organ produces bile, essential for fat digestion and absorption?
20. The primary function of the pyloric sphincter is to:
21. Which nutrient is absorbed primarily in the ileum after complexing with intrinsic factor?
22. Which hormone promotes the contraction of the gallbladder and the relaxation of the sphincter of Oddi?
23. The digestion of nucleic acids (DNA and RNA) into nucleotides and nucleosides is carried out by:
24. Which mineral is absorbed in the duodenum, aided by vitamin C?
25. What is the primary stimulus for the release of gastric inhibitory peptide (GIP)?
26. The enterohepatic circulation primarily involves the recycling of which substance?
27. What is the role of enterokinase (also known as duodenase)?
28. Which part of the small intestine is the primary site for absorption of most nutrients, including carbohydrates, proteins, and fats?
29. The condition characterized by the inability to digest phenylalanine due to a deficiency in the enzyme phenylalanine hydroxylase is known as:
30. Which of the following is NOT considered a salivary gland?
31. Which enzyme is responsible for the breakdown of maltose into glucose?
32. The structure that covers the opening of the trachea during swallowing, preventing food from entering the airway, is the:
33. The primary role of the large intestine in digestion is:
34. What is the function of the Sphincter of Oddi?
35. Which of the following is a hormone that promotes hunger and stimulates appetite?
36. The enzyme that breaks down sucrose into glucose and fructose is:
37. Which of the following is a fat-soluble vitamin that is absorbed along with fats in the small intestine?
38. The primary role of bicarbonate ions secreted by the pancreas is to:
39. Which of the following is a pancreatic enzyme that digests proteins?
40. The absorption of amino acids in the small intestine is an active process that typically requires:

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