MCQs on Digestion and Absorption – CBSE Class 11 Biology
MCQs on Digestion and Absorption – CBSE Class 11 Biology (Unit V | NCERT-Based)
CBSE Class 11 Biology – MCQs with Answers and Explanations
Unit V: Human Physiology
Topic: Digestion and Absorption
Section A: Human Digestive System & Oral Digestion (Q1–Q10)
Q1. Digestion is the process of:
A. Absorption of nutrients
B. Conversion of complex food into simple forms
C. Elimination of waste
D. Transport of food
Answer: B
Explanation: Digestion involves mechanical and chemical breakdown of complex food into absorbable simpler molecules.
Q2. The human alimentary canal starts from mouth and ends at:
A. Rectum
B. Colon
C. Anus
D. Ileum
Answer: C
Explanation: The alimentary canal extends from the mouth to the anus.
Q3. Which teeth are specialized for cutting food?
A. Canines
B. Premolars
C. Molars
D. Incisors
Answer: D
Explanation: Incisors have sharp edges and are used for cutting and biting.
Q4. The enzyme present in saliva is:
A. Pepsin
B. Ptyalin
C. Trypsin
D. Lipase
Answer: B
Explanation: Saliva contains ptyalin (salivary amylase), which digests starch.
Q5. Salivary amylase acts on:
A. Proteins
B. Fats
C. Starch
D. Cellulose
Answer: C
Explanation: Ptyalin converts starch into maltose and dextrins.
Q6. Which structure prevents food from entering the trachea during swallowing?
A. Tongue
B. Glottis
C. Epiglottis
D. Pharynx
Answer: C
Explanation: Epiglottis closes the glottis during swallowing.
Q7. The muscular movement that pushes food through the alimentary canal is:
A. Diffusion
B. Peristalsis
C. Absorption
D. Assimilation
Answer: B
Explanation: Peristalsis involves rhythmic contraction and relaxation of muscles.
Q8. Which part of alimentary canal has no digestion?
A. Mouth
B. Stomach
C. Oesophagus
D. Small intestine
Answer: C
Explanation: Oesophagus only transports food; no digestion occurs.
Q9. The tongue helps in digestion by:
A. Enzyme secretion
B. Mechanical mixing of food
C. Absorbing nutrients
D. Producing bile
Answer: B
Explanation: Tongue helps in mixing food with saliva and swallowing.
Q10. Which type of digestion begins in the mouth?
A. Protein digestion
B. Fat digestion
C. Carbohydrate digestion
D. Vitamin digestion
Answer: C
Explanation: Carbohydrate digestion begins with salivary amylase.
Section B: Stomach & Gastric Digestion (Q11–Q20)
Q11. Gastric glands are present in:
A. Oesophagus
B. Duodenum
C. Stomach
D. Ileum
Answer: C
Explanation: Gastric glands are located in the stomach lining.
Q12. Which acid is present in gastric juice?
A. Sulphuric acid
B. Lactic acid
C. Hydrochloric acid
D. Nitric acid
Answer: C
Explanation: HCl creates acidic pH and activates pepsin.
Q13. Pepsin is secreted in inactive form as:
A. Trypsinogen
B. Pepsinogen
C. Procarboxypeptidase
D. Rennin
Answer: B
Explanation: Pepsinogen is converted into active pepsin by HCl.
Q14. The function of HCl in stomach is to:
A. Digest proteins
B. Kill bacteria and activate enzymes
C. Emulsify fats
D. Absorb nutrients
Answer: B
Explanation: HCl kills microbes and provides acidic pH for enzymes.
Q15. Which enzyme curdles milk in infants?
A. Pepsin
B. Trypsin
C. Rennin
D. Lipase
Answer: C
Explanation: Rennin (chymosin) helps in milk protein digestion in infants.
Q16. Gastric juice does NOT contain:
A. Pepsin
B. HCl
C. Mucus
D. Trypsin
Answer: D
Explanation: Trypsin is a pancreatic enzyme, not gastric.
Q17. Mucus in the stomach helps in:
A. Digestion
B. Absorption
C. Protection of stomach lining
D. Enzyme activation
Answer: C
Explanation: Mucus protects the stomach from acidic damage.
Q18. Proteins are partially digested in stomach into:
A. Amino acids
B. Fatty acids
C. Peptones and proteoses
D. Dipeptides only
Answer: C
Explanation: Pepsin breaks proteins into peptones and proteoses.
Q19. The chyme is:
A. Undigested food
B. Semi-digested acidic food
C. Fully digested food
D. Absorbed nutrients
Answer: B
Explanation: Chyme is semi-digested food mixed with gastric juice.
Q20. Which movement mixes food with gastric juice?
A. Peristalsis
B. Segmentation
C. Diffusion
D. Absorption
Answer: A
Explanation: Peristaltic movements mix food with gastric secretions.
Section C: Pancreatic, Intestinal Digestion & Bile (Q21–Q35)
Q21. Bile is secreted by:
A. Pancreas
B. Gall bladder
C. Liver
D. Duodenum
Answer: C
Explanation: Liver produces bile; gall bladder stores it.
Q22. Bile helps in digestion by:
A. Breaking proteins
B. Emulsifying fats
C. Digesting carbohydrates
D. Activating pepsin
Answer: B
Explanation: Bile salts emulsify fats, increasing surface area.
Q23. Which enzyme converts proteins into peptides in intestine?
A. Pepsin
B. Trypsin
C. Amylase
D. Lipase
Answer: B
Explanation: Trypsin digests proteins and peptides.
Q24. Pancreatic juice does NOT contain:
A. Trypsin
B. Amylase
C. Lipase
D. Maltase
Answer: D
Explanation: Maltase is an intestinal enzyme.
Q25. Pancreatic amylase digests:
A. Cellulose
B. Proteins
C. Starch
D. Fats
Answer: C
Explanation: Pancreatic amylase converts starch to maltose.
Q26. Intestinal juice is also called:
A. Pancreatic juice
B. Bile
C. Succus entericus
D. Gastric juice
Answer: C
Explanation: Intestinal glands secrete succus entericus.
Q27. Which enzyme converts maltose into glucose?
A. Lactase
B. Sucrase
C. Maltase
D. Isomerase
Answer: C
Explanation: Maltase splits maltose into two glucose molecules.
Q28. Which enzyme digests fats completely?
A. Pepsin
B. Amylase
C. Lipase
D. Trypsin
Answer: C
Explanation: Lipase breaks fats into fatty acids and glycerol.
Q29. Final digestion of carbohydrates occurs in:
A. Mouth
B. Stomach
C. Duodenum
D. Intestine
Answer: D
Explanation: Disaccharides are converted into monosaccharides in intestine.
Q30. Which part of small intestine receives bile and pancreatic juice?
A. Jejunum
B. Ileum
C. Duodenum
D. Colon
Answer: C
Explanation: Duodenum receives secretions via hepato-pancreatic duct.
Q31. Enterokinase activates:
A. Pepsinogen
B. Trypsinogen
C. Amylase
D. Lipase
Answer: B
Explanation: Enterokinase converts trypsinogen into active trypsin.
Q32. Complete digestion of proteins results in:
A. Peptides
B. Amino acids
C. Peptones
D. Dipeptides
Answer: B
Explanation: Proteins are finally digested into amino acids.
Q33. Which substance neutralizes acidic chyme?
A. Gastric juice
B. Bile
C. Pancreatic juice
D. Saliva
Answer: B
Explanation: Bile is alkaline and neutralizes acidic chyme.
Q34. Which enzyme is absent in intestinal juice?
A. Maltase
B. Lactase
C. Sucrase
D. Amylase
Answer: D
Explanation: Amylase is secreted by salivary glands and pancreas, not intestine.
Q35. Digestion of fats is maximum in:
A. Stomach
B. Mouth
C. Small intestine
D. Large intestine
Answer: C
Explanation: Emulsification and lipase action occur in small intestine.
Section D: Absorption, Assimilation & Disorders (Q36–Q50)
Q36. Absorption of digested food occurs mainly in:
A. Stomach
B. Large intestine
C. Small intestine
D. Rectum
Answer: C
Explanation: Small intestine is adapted for maximum absorption.
Q37. Finger-like projections in small intestine are called:
A. Alveoli
B. Microvilli
C. Villi
D. Papillae
Answer: C
Explanation: Villi increase surface area for absorption.
Q38. Lacteals are involved in absorption of:
A. Amino acids
B. Glucose
C. Fatty acids
D. Minerals
Answer: C
Explanation: Lacteals absorb digested fats.
Q39. Water-soluble nutrients are absorbed into:
A. Lymph
B. Blood capillaries
C. Lacteals
D. Gall bladder
Answer: B
Explanation: Sugars and amino acids enter blood capillaries.
Q40. Fat absorption occurs mainly by:
A. Diffusion
B. Active transport
C. Pinocytosis
D. Simple osmosis
Answer: A
Explanation: Fatty acids diffuse into epithelial cells after emulsification.
Q41. The process of utilization of absorbed nutrients is called:
A. Digestion
B. Absorption
C. Assimilation
D. Egestion
Answer: C
Explanation: Assimilation refers to use of nutrients by body cells.
Q42. Large intestine mainly absorbs:
A. Proteins
B. Fats
C. Water and salts
D. Vitamins
Answer: C
Explanation: Large intestine absorbs water and electrolytes.
Q43. Egestion refers to:
A. Absorption of nutrients
B. Elimination of undigested food
C. Digestion of food
D. Movement of food
Answer: B
Explanation: Egestion removes undigested waste via anus.
Q44. Which disorder is caused due to lack of lactose digestion?
A. Diarrhoea
B. Lactose intolerance
C. Jaundice
D. Vomiting
Answer: B
Explanation: Deficiency of lactase causes lactose intolerance.
Q45. Jaundice occurs due to accumulation of:
A. Urea
B. Hemoglobin
C. Bilirubin
D. Cholesterol
Answer: C
Explanation: Excess bilirubin causes yellowing of skin and eyes.
Q46. Which disease is characterized by inflammation of stomach lining?
A. Hepatitis
B. Gastritis
C. Appendicitis
D. Cirrhosis
Answer: B
Explanation: Gastritis is inflammation of stomach mucosa.
Q47. Vomiting center is located in:
A. Spinal cord
B. Cerebellum
C. Medulla oblongata
D. Hypothalamus
Answer: C
Explanation: Medulla oblongata controls vomiting reflex.
Q48. Which vitamin is absorbed with fats?
A. Vitamin B
B. Vitamin C
C. Vitamin K
D. Vitamin B₁₂
Answer: C
Explanation: Fat-soluble vitamins (A, D, E, K) need fats for absorption.
Q49. Diarrhoea leads to loss of:
A. Proteins only
B. Vitamins only
C. Water and electrolytes
D. Fats only
Answer: C
Explanation: Excessive water loss causes dehydration.
Q50. Digestion and absorption are essential because they:
A. Provide oxygen
B. Supply energy and raw materials
C. Eliminate waste
D. Regulate temperature
Answer: B
Explanation: Digestion ensures availability of nutrients for energy and growth.