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NEET · Biology · Class 11

Breathing and Exchange of Gases — NEET Biology MCQs

30 questions written by hand against the NCERT chapter. Every wrong option is explained, not just the right one.

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Sample questions from this chapter

A food particle enters the laryngeal opening during swallowing. Which structure most directly failed to guard the airway?
  1. Epiglottis ✓
  2. Pleural membrane
  3. Diaphragm
  4. Nasal turbinate
Answer: A. The epiglottis covers the glottis during swallowing, helping keep food out of the trachea. Its failure creates aspiration risk rather than a ventilation-pressure defect.
Why not B: Pleura reduces friction and couples lungs to the thoracic wall; it does not close the glottis.
Why not C: The diaphragm changes thoracic volume but does not divert swallowed material.
Why not D: Nasal structures condition inspired air rather than protect the larynx during swallowing.
A premature infant lacks enough pulmonary surfactant. Which mechanical problem follows?
  1. Tracheal cartilage becomes too rigid
  2. Pleural fluid becomes blood
  3. Alveoli tend to collapse because surface tension is high ✓
  4. The diaphragm contracts during expiration
Answer: C. Surfactant lowers alveolar surface tension and stabilises small air spaces. Deficiency raises the pressure needed to inflate alveoli and favours collapse after expiration.
Why not A: Surfactant acts at the alveolar air-liquid interface, not on tracheal cartilage.
Why not B: Its deficiency does not convert lubricating pleural fluid into blood.
Why not D: Expiration mechanics do not reverse simply because alveoli are unstable.
Tidal volume is 500 mL, anatomical dead space 150 mL and rate 12 min⁻¹. Which calculation gives alveolar ventilation?
  1. Only dead-space gas counts: 150 × 12 = 1.8 L min⁻¹
  2. The entire tidal volume counts: 500 × 12 = 6.0 L min⁻¹
  3. Dead space is added: 650 × 12 = 7.8 L min⁻¹
  4. Fresh alveolar gas is used: (500−150) × 12 = 4.2 L min⁻¹ ✓
Answer: D. Fresh gas reaching alveoli per breath is 350 mL; multiplied by 12 gives 4.2 L min⁻¹. Rapid shallow breathing can preserve minute ventilation while lowering this value.
Why not A: Dead-space gas does not reach exchange surfaces and must be excluded, not counted alone.
Why not B: Total minute ventilation includes conducting-zone air that does not refresh alveoli.
Why not C: Adding dead space double-counts the non-exchanging portion instead of subtracting it.

These are 3 of the 30 questions in the test. Take the full chapter test →

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Every NCERT question in this chapter is solved, free: NCERT solutions — Breathing and Exchange of Gases →

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Questions

How many NEET questions are there on Breathing and Exchange of Gases?

This chapter test has 30 questions — 10 easy, 14 medium and 6 hard — all written against the NCERT Class 11 chapter.

Is this NEET Biology chapter test free?

Yes. Every chapter test is free with no login. The only paid thing on the site is the full-length 90-question Biology mock and its all-India rank.

Do the questions explain the wrong options?

Yes — every distractor carries its own explanation naming the specific misconception that makes a student pick it. That is the part most question banks skip, and it is the part that changes your next attempt.