Class 11 Biology — Chapter 14: Breathing and Exchange of Gases
60 practice questions · 20 Easy · 20 Medium · 20 Hard
Practise Class 11 Biology Chapter 14, "Breathing and Exchange of Gases", with 60 NCERT-aligned multiple-choice questions. The set is split into 20 Easy, 20 Medium and 20 Hard questions, so you can warm up on the fundamentals and then push into the exam-level problems that separate top scorers in CBSE Board exams and NEET UG.
"Breathing and Exchange of Gases" is one of the chapters where diagram-based recall, terminology and NCERT line-by-line accuracy really pays off. Each MCQ on this chapter is timed and uses exam-grade marking (+2 correct, −1 wrong, 0 skipped), training the same accuracy-under-pressure that real papers demand. Every question carries a short explanation, so a wrong answer becomes a quick lesson rather than a dead end — the fastest way to close gaps before a test.
Use this chapter as targeted revision: attempt the Easy set first to confirm your basics on Breathing and Exchange of Gases, then move to Medium and Hard to test application and problem-solving. Your accuracy, streaks and XP save automatically, and the chapter feeds into your overall Class 11 Biology mastery score. A few sample questions are shown below; sign in free to practise all 60.
Key concepts: Breathing and Exchange of Gases (Class 11 Biology)
This chapter covers the human respiratory system, the mechanism of breathing, and the transport of oxygen and carbon dioxide in blood.
- Respiratory organs
- Air passes through the nasal cavity, pharynx, larynx, trachea, bronchi and bronchioles to the alveoli, where exchange occurs.
- Mechanism of breathing
- Inspiration and expiration result from diaphragm and intercostal muscle action changing thoracic volume and pressure.
- Exchange of gases
- Gases diffuse across alveoli by partial-pressure gradients (O₂ in, CO₂ out).
- Transport of O₂
- Mostly carried as oxyhaemoglobin; the oxygen dissociation curve is sigmoid and shifts with CO₂/pH (Bohr effect).
- Transport of CO₂
- Carried mainly as bicarbonate, plus carbamino-haemoglobin and dissolved forms.
💡 Exam tips for Breathing and Exchange of Gases
- Most CO₂ is transported as bicarbonate ions; most O₂ as oxyhaemoglobin — a common one-mark fact.
- The Bohr effect: higher CO₂/lower pH shifts the O₂ dissociation curve right, releasing more O₂ to tissues.
Sample questions
Site of gas exchange in lungs:
Thin-walled sacs surrounded by capillaries.
Most O₂ in blood is carried by:
~97% bound to Hb as oxyhaemoglobin.
Bohr effect: O₂ binding to Hb decreases when:
Releases O₂ in tissues with high CO₂.
Breathing and Exchange of Gases — FAQs
What are the key concepts in Class 11 Biology Breathing and Exchange of Gases?+
This chapter covers the human respiratory system, the mechanism of breathing, and the transport of oxygen and carbon dioxide in blood. Key ideas include Respiratory organs, Mechanism of breathing, Exchange of gases, Transport of O₂, Transport of CO₂.
What does Class 11 Biology Chapter 14 (Breathing and Exchange of Gases) cover on XamBaaz?+
It covers 60 NCERT-aligned MCQs on "Breathing and Exchange of Gases" — 20 Easy, 20 Medium and 20 Hard — each with a timed quiz and an instant explanation, suitable for CBSE Board exams and NEET UG.
Are these "Breathing and Exchange of Gases" questions free to practise?+
Yes — sign in with Google to practise "Breathing and Exchange of Gases" free. Full unlimited access is ₹999/year (limited-time launch price), with no per-chapter charges.
How should I revise "Breathing and Exchange of Gases" for the exam?+
Start with the Easy quiz to confirm your fundamentals, then attempt Medium and Hard for application-level practice. Review each explanation, retry the questions you miss, and track your accuracy on this chapter until it is consistently high.
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