Chapter 16: Digestion and Absorption – MCQs with Answers & Explanations
CBSE Class 11 Biology Chapter 16 – Digestion and Absorption | MCQs with Answers & Explanations (NCERT)
Course & Examination Details
Course: CBSE Class 11 Biology
Unit: Unit V – Human Physiology
Chapter: Chapter 16 – Digestion and Absorption
Board: Central Board of Secondary Education (CBSE)
Question Type: Multiple Choice Questions (MCQs)
Syllabus: Strictly as per NCERT Biology Textbook
Section A: Human Digestive System (MCQs 1–18)
Q1. Digestion is defined as the process of:
A. Absorption of food
B. Conversion of complex food into simple absorbable substances
C. Utilization of nutrients
D. Elimination of waste
Correct Answer: B
Explanation:
Digestion involves breaking down complex food molecules into simpler, soluble forms that can be absorbed by the body.
Q2. The two main components of the human digestive system are:
A. Mouth and stomach
B. Alimentary canal and respiratory tract
C. Alimentary canal and digestive glands
D. Digestive glands and blood vessels
Correct Answer: C
Explanation:
The digestive system consists of the alimentary canal and associated digestive glands like salivary glands, liver, and pancreas.
Q3. The dental formula of adult humans is:
A. 2132 / 2132
B. 2123 / 2123
C. 2213 / 2213
D. 3122 / 3122
Correct Answer: B
Explanation:
Adult humans have two incisors, one canine, two premolars, and three molars on each side of both jaws.
Q4. Which enzyme is present in saliva?
A. Pepsin
B. Trypsin
C. Salivary amylase
D. Lipase
Correct Answer: C
Explanation:
Salivary amylase initiates digestion of starch in the mouth.
Q5. Peristalsis helps in:
A. Digestion of food
B. Absorption of nutrients
C. Movement of food along the alimentary canal
D. Enzyme secretion
Correct Answer: C
Explanation:
Peristalsis is the wave-like muscular movement that propels food through the digestive tract.
Q6. Which acid is secreted by the stomach?
A. Sulphuric acid
B. Nitric acid
C. Hydrochloric acid
D. Acetic acid
Correct Answer: C
Explanation:
Hydrochloric acid provides acidic medium and activates pepsinogen.
Q7. The semi-fluid food formed in the stomach is called:
A. Bolus
B. Chyme
C. Chylomicron
D. Faeces
Correct Answer: B
Explanation:
Chyme is the partially digested, acidic food formed in the stomach.
Q8. Protein digestion begins in the:
A. Mouth
B. Oesophagus
C. Stomach
D. Small intestine
Correct Answer: C
Explanation:
Pepsin initiates protein digestion in the stomach.
Q9. The longest part of the alimentary canal is the:
A. Stomach
B. Large intestine
C. Small intestine
D. Oesophagus
Correct Answer: C
Explanation:
The small intestine is the longest part and main site of digestion and absorption.
Q10. The first part of the small intestine is the:
A. Ileum
B. Jejunum
C. Duodenum
D. Colon
Correct Answer: C
Explanation:
The duodenum receives bile and pancreatic juice.
Q11. Which organ stores bile?
A. Liver
B. Pancreas
C. Gall bladder
D. Duodenum
Correct Answer: C
Explanation:
The gall bladder stores and concentrates bile.
Q12. Which secretion protects the stomach lining?
A. Pepsin
B. Mucus
C. HCl
D. Rennin
Correct Answer: B
Explanation:
Mucus prevents damage to the stomach wall by acid and enzymes.
Q13. Which movement ensures food transport even against gravity?
A. Segmentation
B. Diffusion
C. Peristalsis
D. Absorption
Correct Answer: C
Explanation:
Peristaltic movements push food irrespective of body position.
Q14. The large intestine mainly absorbs:
A. Proteins
B. Fats
C. Water and electrolytes
D. Glucose
Correct Answer: C
Explanation:
The large intestine absorbs water and salts from undigested food.
Q15. Egestion refers to:
A. Removal of metabolic waste
B. Removal of undigested food
C. Absorption of nutrients
D. Utilization of food
Correct Answer: B
Explanation:
Egestion is elimination of undigested and unabsorbed food.
Q16. The largest gland in the human body is:
A. Pancreas
B. Liver
C. Salivary gland
D. Thyroid
Correct Answer: B
Explanation:
The liver is the largest gland and plays a major role in digestion and metabolism.
Q17. Which substance kills bacteria in food?
A. Saliva
B. Mucus
C. Hydrochloric acid
D. Pepsin
Correct Answer: C
Explanation:
Hydrochloric acid destroys harmful microorganisms in food.
Q18. Which structure temporarily stores faeces?
A. Colon
B. Caecum
C. Rectum
D. Anus
Correct Answer: C
Explanation:
The rectum stores faeces before defecation.
Section B: Digestive Enzymes (MCQs 19–35)
Q19. Salivary amylase digests:
A. Proteins
B. Fats
C. Starch
D. Cellulose
Correct Answer: C
Explanation:
Salivary amylase converts starch into maltose.
Q20. Which enzyme digests proteins in the stomach?
A. Trypsin
B. Pepsin
C. Lipase
D. Rennin
Correct Answer: B
Explanation:
Pepsin digests proteins into proteoses and peptones.
Q21. Pepsinogen is activated by:
A. Bile
B. Trypsin
C. Hydrochloric acid
D. Enterokinase
Correct Answer: C
Explanation:
HCl converts pepsinogen into active pepsin.
Q22. Which enzyme digests fats?
A. Amylase
B. Pepsin
C. Lipase
D. Trypsin
Correct Answer: C
Explanation:
Lipase breaks fats into fatty acids and glycerol.
Q23. Bile helps in digestion by:
A. Digesting proteins
B. Digesting fats
C. Emulsifying fats
D. Digesting starch
Correct Answer: C
Explanation:
Bile salts emulsify fats, increasing surface area.
Q24. Which enzyme digests lactose?
A. Maltase
B. Sucrase
C. Lactase
D. Amylase
Correct Answer: C
Explanation:
Lactase breaks lactose into glucose and galactose.
Q25. Trypsinogen is activated into trypsin by:
A. Pepsin
B. HCl
C. Enterokinase
D. Lipase
Correct Answer: C
Explanation:
Enterokinase activates trypsinogen in the intestine.
Q26. Digestion of fats occurs mainly in the:
A. Mouth
B. Stomach
C. Small intestine
D. Large intestine
Correct Answer: C
Explanation:
Fat digestion occurs in alkaline medium of the small intestine.
Q27. Which enzyme digests nucleic acids?
A. Pepsin
B. Lipase
C. Nuclease
D. Amylase
Correct Answer: C
Explanation:
Pancreatic nucleases digest nucleic acids.
Q28. Which of the following is NOT present in bile?
A. Bile salts
B. Pigments
C. Digestive enzymes
D. Cholesterol
Correct Answer: C
Explanation:
Bile contains no digestive enzymes.
Q29. Rennin is found in:
A. Adults
B. Infants
C. Old age
D. All age groups
Correct Answer: B
Explanation:
Rennin helps digest milk proteins in infants.
Q30. Which enzyme completes protein digestion?
A. Pepsin
B. Trypsin
C. Peptidase
D. Amylase
Correct Answer: C
Explanation:
Peptidases convert peptides into amino acids.
Q31. Pancreatic juice provides a medium that is:
A. Acidic
B. Neutral
C. Alkaline
D. Variable
Correct Answer: C
Explanation:
An alkaline medium is required for pancreatic enzymes.
Q32. Disaccharides are converted into monosaccharides by:
A. Pancreatic enzymes
B. Gastric enzymes
C. Intestinal enzymes
D. Salivary enzymes
Correct Answer: C
Explanation:
Intestinal enzymes like maltase and sucrase complete digestion.
Q33. Lactose intolerance is caused by deficiency of:
A. Amylase
B. Maltase
C. Lactase
D. Lipase
Correct Answer: C
Explanation:
Lack of lactase prevents lactose digestion.
Q34. Which enzyme digests starch in the intestine?
A. Salivary amylase
B. Pancreatic amylase
C. Pepsin
D. Lipase
Correct Answer: B
Explanation:
Pancreatic amylase continues starch digestion in intestine.
Q35. Which condition helps enzymes act efficiently in intestine?
A. Acidic medium
B. Neutral medium
C. Alkaline medium
D. Cold temperature
Correct Answer: C
Explanation:
Most intestinal enzymes require alkaline pH.
Section C: Absorption Process (MCQs 36–50)
Q36. Absorption occurs mainly in the:
A. Stomach
B. Oesophagus
C. Small intestine
D. Large intestine
Correct Answer: C
Explanation:
Small intestine is the main site of absorption.
Q37. Finger-like projections in the intestine are called:
A. Alveoli
B. Villi
C. Nephrons
D. Papillae
Correct Answer: B
Explanation:
Villi increase surface area for absorption.
Q38. Microvilli are present on:
A. Blood capillaries
B. Lacteals
C. Intestinal epithelial cells
D. Muscle cells
Correct Answer: C
Explanation:
Microvilli form the brush border of epithelial cells.
Q39. Glucose is absorbed by:
A. Simple diffusion
B. Active transport
C. Osmosis
D. Pinocytosis
Correct Answer: B
Explanation:
Glucose absorption requires energy via active transport.
Q40. Fats are absorbed in the form of:
A. Glucose
B. Amino acids
C. Chylomicrons
D. Peptides
Correct Answer: C
Explanation:
Fats are transported as chylomicrons through lymph.
Q41. Lacteals are involved in absorption of:
A. Proteins
B. Carbohydrates
C. Fats
D. Minerals
Correct Answer: C
Explanation:
Lacteals absorb fats into the lymphatic system.
Q42. Fat-soluble vitamins include:
A. B and C
B. A, D, E, K
C. B₁, B₂
D. C and K
Correct Answer: B
Explanation:
Fat-soluble vitamins are absorbed along with fats.
Q43. Minerals like calcium are absorbed by:
A. Diffusion only
B. Active transport
C. Osmosis
D. Pinocytosis
Correct Answer: B
Explanation:
Calcium requires active transport for absorption.
Q44. Which substance can be absorbed in the stomach?
A. Proteins
B. Fats
C. Alcohol
D. Starch
Correct Answer: C
Explanation:
Alcohol can be absorbed directly from the stomach.
Q45. Utilization of absorbed nutrients is called:
A. Digestion
B. Absorption
C. Assimilation
D. Egestion
Correct Answer: C
Explanation:
Assimilation refers to use of nutrients by body cells.
Q46. Removal of faeces is called:
A. Excretion
B. Assimilation
C. Egestion
D. Digestion
Correct Answer: C
Explanation:
Egestion eliminates undigested waste.
Q47. Diarrhoea leads to:
A. Weight gain
B. Dehydration
C. Protein synthesis
D. Fat absorption
Correct Answer: B
Explanation:
Diarrhoea causes excessive loss of water and salts.
Q48. Constipation occurs due to:
A. Increased motility
B. Decreased water absorption
C. Excess water absorption
D. Enzyme deficiency
Correct Answer: C
Explanation:
Excess water absorption makes stools hard.
Q49. Jaundice is related to malfunctioning of:
A. Pancreas
B. Kidney
C. Liver
D. Intestine
Correct Answer: C
Explanation:
Jaundice occurs due to accumulation of bile pigments.
Q50. Increased surface area for absorption is mainly due to:
A. Muscular walls
B. Intestinal glands
C. Villi and microvilli
D. Blood supply
Correct Answer: C
Explanation:
Villi and microvilli greatly enhance absorptive efficiency.
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