Chapter 16: Digestion and Absorption – Very Short Answer Type Questions
CBSE Class 11 Biology Chapter 16 – Digestion and Absorption | Very Short Answer Questions (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: Very Short Answer Questions
Answer Length: 20–30 words
Syllabus: Strictly as per NCERT Biology Textbook
Section A: Human Digestive System (Q1–Q18)
Q1. What is digestion?
Answer:
Digestion is the process by which complex food substances are broken down into simpler, soluble forms that can be absorbed and utilized by the body.
Q2. Name the two main components of the human digestive system.
Answer:
The human digestive system consists of the alimentary canal and associated digestive glands such as salivary glands, liver, and pancreas.
Q3. What is the alimentary canal?
Answer:
The alimentary canal is a continuous muscular tube extending from the mouth to the anus, responsible for ingestion, digestion, absorption, and egestion.
Q4. State one function of teeth.
Answer:
Teeth help in mastication by mechanically breaking food into smaller pieces, increasing the surface area for enzyme action.
Q5. What is the dental formula of adult humans?
Answer:
The dental formula of adult humans is 2123 / 2123, representing incisors, canines, premolars, and molars in each jaw.
Q6. Mention one function of the tongue.
Answer:
The tongue helps in mixing food with saliva, swallowing, and perception of taste through taste buds present on its surface.
Q7. Name the three pairs of salivary glands.
Answer:
The three pairs of salivary glands are parotid, submandibular, and sublingual glands.
Q8. Which enzyme is present in saliva?
Answer:
Salivary amylase, also called ptyalin, is present in saliva and initiates the digestion of starch.
Q9. What is peristalsis?
Answer:
Peristalsis is the rhythmic contraction and relaxation of muscles of the alimentary canal that helps in the movement of food.
Q10. Name the regions of the stomach.
Answer:
The stomach has three regions: cardiac, fundic, and pyloric regions.
Q11. Which acid is secreted by gastric glands?
Answer:
Hydrochloric acid (HCl) is secreted by gastric glands to provide an acidic medium for enzyme action.
Q12. What is chyme?
Answer:
Chyme is the semi-fluid, acidic mixture of partially digested food formed in the stomach.
Q13. Name the longest part of the alimentary canal.
Answer:
The small intestine is the longest part of the alimentary canal and is the main site of digestion and absorption.
Q14. List the parts of the small intestine.
Answer:
The small intestine is divided into duodenum, jejunum, and ileum.
Q15. State one function of the large intestine.
Answer:
The large intestine absorbs water and electrolytes from undigested food and helps in formation of faeces.
Q16. What is egestion?
Answer:
Egestion is the process of elimination of undigested and unabsorbed food from the body through the anus.
Q17. Which organ stores bile?
Answer:
The gall bladder stores and concentrates bile produced by the liver.
Q18. Name the largest gland in the human body.
Answer:
The liver is the largest gland in the human body and plays a vital role in digestion and metabolism.
Section B: Digestive Enzymes (Q19–Q35)
Q19. What is bile?
Answer:
Bile is a digestive fluid secreted by the liver that contains bile salts and helps in emulsification of fats.
Q20. Does bile contain enzymes?
Answer:
No, bile does not contain digestive enzymes but facilitates fat digestion by emulsifying fats.
Q21. Name the digestive juice secreted by the pancreas.
Answer:
The pancreas secretes pancreatic juice containing enzymes for digestion of carbohydrates, proteins, fats, and nucleic acids.
Q22. Which enzyme converts starch into maltose in the mouth?
Answer:
Salivary amylase converts starch into maltose in the mouth.
Q23. Name the enzyme that digests proteins in the stomach.
Answer:
Pepsin digests proteins into proteoses and peptones in the acidic environment of the stomach.
Q24. Which substance activates pepsinogen?
Answer:
Hydrochloric acid activates pepsinogen into active pepsin.
Q25. Name one proteolytic enzyme of pancreatic juice.
Answer:
Trypsin is a proteolytic enzyme of pancreatic juice that digests proteins into smaller peptides.
Q26. Which enzyme digests fats in the small intestine?
Answer:
Pancreatic lipase digests fats into fatty acids and glycerol in the small intestine.
Q27. What is emulsification of fats?
Answer:
Emulsification is the process of breaking large fat globules into smaller droplets by bile salts.
Q28. Name enzymes that convert disaccharides into monosaccharides.
Answer:
Maltase, sucrase, and lactase convert disaccharides into monosaccharides.
Q29. Which enzyme digests lactose?
Answer:
Lactase digests lactose into glucose and galactose.
Q30. Where does maximum digestion occur?
Answer:
Maximum digestion occurs in the small intestine due to the combined action of pancreatic and intestinal enzymes.
Q31. Which enzyme digests nucleic acids?
Answer:
Pancreatic nucleases digest nucleic acids into nucleotides.
Q32. In which medium does fat digestion occur?
Answer:
Fat digestion occurs in an alkaline medium of the small intestine.
Q33. What is the role of mucus in gastric juice?
Answer:
Mucus protects the stomach lining from the corrosive action of hydrochloric acid and digestive enzymes.
Q34. Name the enzyme present in intestinal juice that digests peptides.
Answer:
Peptidases present in intestinal juice digest peptides into amino acids.
Q35. Which digestive enzyme is absent in bile?
Answer:
All digestive enzymes are absent in bile; it contains only bile salts and pigments.
Section C: Absorption Process (Q36–Q50)
Q36. What is absorption?
Answer:
Absorption is the process by which digested nutrients pass through the intestinal mucosa into blood or lymph.
Q37. Name the structures that increase absorptive surface area.
Answer:
Villi and microvilli increase the surface area of the small intestine for efficient absorption.
Q38. Where does most absorption occur?
Answer:
Most absorption of nutrients occurs in the small intestine, especially in the jejunum and ileum.
Q39. How are glucose and amino acids absorbed?
Answer:
Glucose and amino acids are absorbed by active transport and facilitated diffusion mechanisms.
Q40. How are fatty acids and glycerol absorbed?
Answer:
Fatty acids and glycerol are absorbed as micelles and transported through lymph as chylomicrons.
Q41. What are chylomicrons?
Answer:
Chylomicrons are lipoprotein particles that transport absorbed fats from intestinal cells into the lymph.
Q42. Name one substance absorbed in the stomach.
Answer:
Alcohol is absorbed in small amounts through the stomach lining.
Q43. Which vitamins are absorbed along with fats?
Answer:
Fat-soluble vitamins A, D, E, and K are absorbed along with fats.
Q44. How are minerals absorbed?
Answer:
Minerals are absorbed by passive diffusion or active transport depending on their concentration and requirement.
Q45. What is assimilation?
Answer:
Assimilation is the utilization of absorbed nutrients by body cells for energy, growth, and repair.
Q46. What is defecation?
Answer:
Defecation is the process of expelling faeces from the rectum through the anus.
Q47. Name one disorder of the digestive system.
Answer:
Diarrhoea is a digestive disorder characterized by frequent watery stools and loss of water.
Q48. What causes jaundice?
Answer:
Jaundice is caused by malfunctioning of the liver leading to accumulation of bile pigments in the blood.
Q49. Why is the small intestine highly coiled?
Answer:
The small intestine is highly coiled to increase surface area and allow more time for digestion and absorption.
Q50. State one function of the large intestine besides absorption.
Answer:
The large intestine helps in compaction of waste and temporary storage of faeces before egestion.