Gaseous Exchange is the first chapter of Class 10 Biology and explains how living organisms obtain oxygen and remove carbon dioxide. This chapter covers breathing, respiration, respiratory organs in plants and animals, human respiratory system, and common respiratory disorders. This post includes carefully prepared Class 10 Biology Chapter 1 MCQs to help students revise important concepts according to Punjab and Sindh Board syllabus.
1. Gaseous exchange in humans takes place in:
- A. Trachea
- B. Bronchi
- C. Alveoli ✅
- D. Larynx
Explanation: Alveoli provide a large surface area for diffusion of oxygen and carbon dioxide.
2. Which gas is taken in during breathing?
- A. Oxygen ✅
- B. Carbon dioxide
- C. Nitrogen
- D. Hydrogen
Explanation: Oxygen is required for cellular respiration.
3. Breathing is best described as:
- A. Breakdown of glucose
- B. Movement of air in and out of lungs ✅
- C. Exchange of gases in tissues
- D. Release of energy
Explanation: Breathing involves inhalation and exhalation of air.
4. Respiration differs from breathing because respiration:
- A. Occurs only in lungs
- B. Is voluntary
- C. Releases energy from food ✅
- D. Is a physical process
Explanation: Respiration is a chemical process that releases energy.
5. Which structure prevents food from entering the trachea?
- A. Larynx
- B. Epiglottis ✅
- C. Bronchi
- D. Pharynx
Explanation: Epiglottis closes the trachea during swallowing.
6. The exchange of gases in plants mainly occurs through:
- A. Roots
- B. Stomata ✅
- C. Xylem
- D. Phloem
Explanation: Stomata allow diffusion of gases in leaves.
7. Which gas is released during respiration?
- A. Oxygen
- B. Carbon dioxide ✅
- C. Nitrogen
- D. Methane
Explanation: Carbon dioxide is produced as a waste product of respiration.
8. The process by which oxygen moves from alveoli to blood is called:
- A. Active transport
- B. Diffusion ✅
- C. Osmosis
- D. Filtration
Explanation: Gases move across membranes by diffusion.
9. Which respiratory disorder is caused by inflammation of airways?
- A. Pneumonia
- B. Asthma ✅
- C. Tuberculosis
- D. Emphysema
Explanation: Asthma causes narrowing of bronchi due to inflammation.
10. Which pigment in red blood cells transports oxygen?
- A. Myoglobin
- B. Hemoglobin ✅
- C. Chlorophyll
- D. Plasma
Explanation: Hemoglobin binds oxygen for transport in blood.
11. Inhalation occurs when:
- A. Diaphragm relaxes
- B. Diaphragm contracts ✅
- C. Chest cavity decreases
- D. Lungs shrink
Explanation: Diaphragm contraction increases chest volume.
12. Which disease is caused by Mycobacterium tuberculosis?
- A. Asthma
- B. Tuberculosis ✅
- C. Bronchitis
- D. Influenza
Explanation: Tuberculosis is a bacterial lung infection.
13. Which structure connects larynx to bronchi?
- A. Pharynx
- B. Trachea ✅
- C. Alveoli
- D. Diaphragm
Explanation: Trachea carries air to bronchi.
14. The rate of breathing is controlled by:
- A. Heart
- B. Lungs
- C. Medulla oblongata ✅
- D. Spinal cord
Explanation: Breathing is regulated by the brainstem.
15. Which gas has the highest concentration in inhaled air?
- A. Oxygen
- B. Nitrogen ✅
- C. Carbon dioxide
- D. Water vapor
Explanation: Nitrogen makes up about 78% of air.
16. Which structure increases surface area for gas exchange?
- A. Bronchi
- B. Alveoli ✅
- C. Trachea
- D. Larynx
Explanation: Numerous alveoli provide large surface area.
17. Which process removes carbon dioxide from blood?
- A. Inhalation
- B. Exhalation ✅
- C. Respiration
- D. Digestion
Explanation: CO₂ is expelled during exhalation.
18. Smoking mainly damages which part of respiratory system?
- A. Pharynx
- B. Trachea
- C. Alveoli ✅
- D. Larynx
Explanation: Smoking destroys alveoli and reduces oxygen exchange.