NEET · Biology · Class 11Breathing 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?
- Epiglottis ✓
- Pleural membrane
- Diaphragm
- 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?
- Tracheal cartilage becomes too rigid
- Pleural fluid becomes blood
- Alveoli tend to collapse because surface tension is high ✓
- 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?
- 1800 mL min⁻¹
- 6000 mL min⁻¹
- 7800 mL min⁻¹
- 4200 mL 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.
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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, and you get your all-India rank on every one. Nothing on the site is on sale right now.
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.