Class 11 Biology MCQ Chapter 14 Breathing and Exchange of Gases
Are you preparing for your Biology examination and looking for Class 11 Biology MCQ Chapter 14 Breathing and Exchange of Gases English Medium? This article provides a collection of important MCQ questions with answers that will help AHSEC Higher Secondary First Year students revise the chapter effectively.
The chapter Breathing and Exchange of Gases explains how the human body takes in oxygen and removes carbon dioxide. Students will learn about the respiratory system, mechanism of breathing, exchange and transport of gases, respiratory volumes, lung capacity, and common respiratory disorders. These concepts are essential for understanding how the body obtains energy and maintains normal life processes.
The MCQs are prepared according to the latest AHSEC syllabus and examination pattern. They are useful for quick revision, self-assessment, and strengthening important concepts before examinations. Solving these questions regularly can improve understanding and help students answer objective questions more confidently.
Whether you are preparing for class tests, annual exams, or the AHSEC HS First Year Examination, these MCQ solutions will support your Biology preparation and help you achieve better results.
Unit V. Human Physiology
Breathing and Exchange of Gases
VSA & MCQ
I. Short Answer Questions (1 Mark Each)
1. What is breathing?
Ans: Breathing is the physical process of inhalation (taking in O₂) and exhalation (giving out CO₂).
2. What is respiration?
Ans: Respiration is the biochemical process of oxidation of food to release energy.
3. What is tidal volume (TV)?
Ans: It is the volume of air inhaled or exhaled during normal breathing (~500 mL).
4. Define residual volume (RV).
Ans: The volume of air remaining in the lungs after maximum forced expiration (~1100–1200 mL).
5. What is inspiratory reserve volume (IRV)?
Ans: Extra air that can be inhaled after normal inspiration (~2500–3000 mL).
6. What is expiratory reserve volume (ERV)?
Ans: Extra air that can be exhaled after normal expiration (~1000–1100 mL).
7. What is vital capacity (VC)?
Ans: Maximum air expelled after maximum inhalation (TV + IRV + ERV).
8. What is total lung capacity (TLC)?
Ans: Total volume of lungs (VC + RV).
9. What is the function of haemoglobin?
Ans: It transports oxygen from lungs to tissues and partly CO₂ back to lungs.
10. What is Bohr effect?
Ans: Increased CO₂ reduces affinity of haemoglobin for O₂, aiding oxygen release.
11. What are alveoli?
Ans: Tiny air sacs in lungs where gaseous exchange occurs.
12. What is surfactant?
Ans: A lipoprotein that reduces surface tension in alveoli and prevents collapse.
13. What is hypoxia?
Ans: A condition of insufficient oxygen supply to tissues.
14. What is cyanosis?
Ans: Bluish discoloration of skin due to lack of oxygen.
15. What is the role of carbonic anhydrase?
Ans: It catalyzes conversion of CO₂ into bicarbonate in RBCs.
II. Multiple Choice Questions (MCQs)
1. The respiratory pigment in humans is:
(a) Myoglobin
(b) Haemoglobin
(c) Chlorophyll
(d) Haemocyanin
Ans: (b)
2. Normal tidal volume is about:
(a) 100 mL
(b) 500 mL
(c) 1500 mL
(d) 3000 mL
Ans: (b)
3. Gas exchange occurs in:
(a) Bronchi
(b) Trachea
(c) Alveoli
(d) Larynx
Ans: (c)
4. The functional unit of lungs is:
(a) Nephron
(b) Alveolus
(c) Trachea
(d) Bronchiole
Ans: (b)
5. Oxygen is transported mainly as:
(a) Dissolved in plasma
(b) Oxyhaemoglobin
(c) Carbamino compounds
(d) Bicarbonate
Ans: (b)
6. CO₂ is mostly transported as:
(a) Carbamino Hb
(b) Dissolved gas
(c) Bicarbonate
(d) CO₂ bubbles
Ans: (c)
7. The respiratory centre is located in:
(a) Cerebrum
(b) Medulla oblongata
(c) Cerebellum
(d) Hypothalamus
Ans: (b)
8. Surfactant prevents:
(a) Gas exchange
(b) Lung collapse
(c) Breathing
(d) Oxygen transport
Ans: (b)
9. Bohr effect is related to:
(a) CO₂ effect on Hb
(b) O₂ effect on CO₂
(c) Pressure changes
(d) Lung volume
Ans: (a)
10. Residual volume is about:
(a) 500 mL
(b) 1000–1200 mL
(c) 3000 mL
(d) 6000 mL
Ans: (b)
11. Which gas has higher diffusion rate?
(a) O₂
(b) CO₂
(c) N₂
(d) H₂
Ans: (b)
12. Pneumotaxic centre is present in:
(a) Pons
(b) Medulla
(c) Cerebrum
(d) Spinal cord
Ans: (a)
13. Normal breathing rate is:
(a) 5/min
(b) 12–16/min
(c) 30/min
(d) 50/min
Ans: (b)
14. Which volume cannot be measured by spirometer?
(a) TV
(b) IRV
(c) ERV
(d) RV
Ans: (d)
15. Oxygen dissociation curve is:
(a) Linear
(b) Hyperbolic
(c) Sigmoidal
(d) Parabolic
Ans: (c)
16. Trachea is supported by:
(a) Bones
(b) Cartilage rings
(c) Muscles
(d) Ligaments
Ans: (b)
17. External intercostal muscles help in:
(a) Expiration
(b) Inspiration
(c) Digestion
(d) Circulation
Ans: (b)
18. Insects respire through:
(a) Lungs
(b) Gills
(c) Tracheae
(d) Skin
Ans: (c)
19. Hypoxia occurs due to:
(a) High O₂
(b) Low O₂
(c) High CO₂
(d) Low CO₂
Ans: (b)
20. Cyanosis indicates:
(a) High oxygen
(b) Low oxygen
(c) High sugar
(d) Low sugar
Ans: (b)
21. Haemoglobin contains:
(a) Calcium
(b) Iron
(c) Sodium
(d) Potassium
Ans: (b)
22. Functional residual capacity =
(a) TV + IRV
(b) ERV + RV
(c) TV + ERV
(d) IRV + RV
Ans: (b)
23. Vital capacity excludes:
(a) TV
(b) IRV
(c) ERV
(d) RV
Ans: (d)
24. Diffusion depends on:
(a) Pressure gradient
(b) Temperature
(c) Surface area
(d) All of these
Ans: (d)
25. CO₂ transport involves enzyme:
(a) Amylase
(b) Carbonic anhydrase
(c) Pepsin
(d) Trypsin
Ans: (b)
26. Maximum air lungs can hold is:
(a) VC
(b) TLC
(c) RV
(d) TV
Ans: (b)
27. Diaphragm contracts during:
(a) Expiration
(b) Inspiration
(c) Rest
(d) Digestion
Ans: (b)
28. Alveoli are lined by:
(a) Cuboidal epithelium
(b) Squamous epithelium
(c) Columnar epithelium
(d) Stratified epithelium
Ans: (b)
29. Oxygen binds to:
(a) Globin
(b) Heme
(c) Plasma
(d) Platelets
Ans: (b)
30. Normal pH of blood is:
(a) 6.8
(b) 7.4
(c) 8.0
(d) 5.5
Ans: (b)
