Chapter 16: Digestion and Absorption – Case-Based / Source-Based Questions with Answers

CBSE Class 11 Biology Chapter 16 – Digestion and Absorption | Case-Based / Source-Based 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: Case-Based / Source-Based Questions
Syllabus: Strictly as per NCERT Biology Textbook

Section A: Human Digestive System (Case 1–9)

Case 1

A student chews a piece of bread for a long time and notices a slightly sweet taste.

Q1. Why does the food start tasting sweet?
Answer:
Salivary amylase present in saliva converts starch in bread into maltose, which gives a sweet taste.

Q2. Name the digestive process occurring here.
Answer:
Chemical digestion of carbohydrates is occurring in the buccal cavity.

Case 2

Food passes smoothly from the oesophagus to the stomach even when a person is upside down.

Q3. Which movement enables this transport?
Answer:
Peristalsis enables the movement of food through the oesophagus.

Q4. Define peristalsis.
Answer:
Peristalsis is the rhythmic contraction and relaxation of muscles of the alimentary canal that propels food forward.

Case 3

A patient shows damage to the stomach lining due to excessive acid secretion.

Q5. Which secretion normally protects the stomach lining?
Answer:
Mucus protects the stomach lining from the corrosive action of hydrochloric acid.

Q6. Name the acid secreted by gastric glands.
Answer:
Hydrochloric acid (HCl) is secreted by gastric glands.

Case 4

Partially digested food leaves the stomach and enters the small intestine.

Q7. What is this semi-fluid food called?
Answer:
The semi-fluid food is called chyme.

Q8. Name the part of the small intestine that receives chyme first.
Answer:
The duodenum receives chyme from the stomach.

Case 5

A doctor explains that most digestion occurs in a specific part of the alimentary canal.

Q9. Which part is this and why?
Answer:
The small intestine, because it receives pancreatic juice, bile, and intestinal juice that complete digestion.

Section B: Digestive Glands and Enzymes (Case 10–17)

Case 6

A child is unable to digest milk properly and shows bloating and diarrhoea.

Q10. Which enzyme is deficient in this condition?
Answer:
Lactase enzyme is deficient.

Q11. Name the condition.
Answer:
The condition is lactose intolerance.

Case 7

A patient’s pancreatic duct is blocked, affecting digestion.

Q12. Which digestive juice will not reach the intestine?
Answer:
Pancreatic juice will not reach the small intestine.

Q13. Name one enzyme affected due to this blockage.
Answer:
Trypsin (or pancreatic amylase or lipase) will be affected.

Case 8

Fat digestion is poor even though pancreatic enzymes are present.

Q14. Which secretion is likely deficient?
Answer:
Bile secretion is likely deficient.

Q15. State one role of this secretion in digestion.
Answer:
Bile emulsifies fats into smaller droplets, increasing surface area for lipase action.

Case 9

A student observes that protein digestion begins in the stomach.

Q16. Name the enzyme responsible.
Answer:
Pepsin is responsible for protein digestion in the stomach.

Q17. Which substance activates this enzyme?
Answer:
Hydrochloric acid activates pepsinogen into pepsin.

Section C: Absorption Process (Case 18–22)

Case 10

Microscopic observation of the small intestine shows finger-like projections.

Q18. Name these structures.
Answer:
These structures are called villi.

Q19. State their significance.
Answer:
Villi increase surface area for efficient absorption of nutrients.

Case 11

After a fatty meal, fats are transported through lymph instead of blood.

Q20. In which form are fats transported?
Answer:
Fats are transported as chylomicrons.

Case 12

A patient consumes glucose solution during dehydration and feels energetic quickly.

Q21. How is glucose absorbed?
Answer:
Glucose is absorbed by active transport and facilitated diffusion into blood capillaries.

Case 13

A doctor explains that alcohol enters the bloodstream rapidly.

Q22. From which organ is alcohol absorbed?
Answer:
Alcohol is absorbed from the stomach.

Section D: Assimilation, Egestion & Disorders (Case 23–25)

Case 14

After absorption, nutrients are transported to different tissues for use.

Q23. Name the process of utilization of absorbed nutrients.
Answer:
The process is called assimilation.

Case 15

A person suffers from frequent watery stools due to infection.

Q24. Identify the disorder.
Answer:
The disorder is diarrhoea.

Case 16

A patient shows yellowing of eyes and skin due to liver malfunction.

Q25. Name this condition.
Answer:
The condition is jaundice, caused by accumulation of bile pigments in blood.

Conclusion

These 25 Case-Based / Source-Based Questions with Answers are:

• Fully aligned with NCERT Biology
• Designed as per CBSE Class 11 competency-based pattern
• Ideal for board exams, internal assessments, and revision
• Focused on application, reasoning, and concept clarity