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Breathing and Exchange of Gases Practice Questions

Class 11 · Biology · 2297 free MCQs with instant results and detailed explanations.

2297
Total
672
Easy
1152
Medium
473
Hard

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Topics in Breathing and Exchange of Gases

Respiratory Organs 580
Mechanism of Breathing 572
Respiratory Disorders 607
Exchange of Gases 538

Sample Questions from Breathing and Exchange of Gases

Here are 10 sample questions. Start a quiz to get randomized questions with scoring.

Q1
Easy
Which of the following organs is primarily responsible for gas exchange in humans?
A. Lungs
B. Heart
C. Kidneys
D. Liver
Show Answer & Explanation
Correct Answer: A
The lungs are the primary organs for gas exchange, allowing oxygen to enter the bloodstream and carbon dioxide to be expelled.
Q2
Easy
What is the main function of the diaphragm in the respiratory process?
A. To filter air
B. To increase lung volume
C. To warm the air
D. To produce sound
Show Answer & Explanation
Correct Answer: B
The diaphragm is a muscle that contracts and flattens to increase the volume of the thoracic cavity, allowing the lungs to expand and fill with air.
Q3
Easy
Which of the following statements about alveoli is true?
A. They are the site of oxygen absorption only.
B. They increase the surface area for gas exchange.
C. They are filled with fluid to aid gas exchange.
D. They are located in the trachea.
Show Answer & Explanation
Correct Answer: B
Alveoli are tiny air sacs in the lungs that provide a large surface area for gas exchange, making them crucial for effective respiration.
Q4
Medium
What is the primary function of the alveoli in the lungs?
A. Gas exchange between air and blood
B. Production of mucus
C. Regulation of blood pH
D. Movement of air in and out
Show Answer & Explanation
Correct Answer: A
Alveoli are tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out.
Q5
Medium
Which of the following is NOT a feature of respiratory surfaces?
A. Thin-walled
B. Moist
C. Highly vascularized
D. Impermeable to gases
Show Answer & Explanation
Correct Answer: D
Respiratory surfaces must be permeable to gases to allow for efficient gas exchange.
Q6
Medium
In humans, which structure is primarily responsible for producing sound?
A. Trachea
B. Larynx
C. Bronchi
D. Pharynx
Show Answer & Explanation
Correct Answer: B
The larynx contains the vocal cords which vibrate to produce sound.
Q7
Medium
What prevents the collapse of the alveoli during breathing?
A. Surfactant
B. Mucus
C. Blood pressure
D. Cilia
Show Answer & Explanation
Correct Answer: A
Surfactant reduces surface tension in the alveoli, preventing their collapse.
Q8
Hard
Which of the following structures is primarily responsible for gas exchange in the human lungs?
A. Alveoli
B. Bronchi
C. Trachea
D. Diaphragm
Show Answer & Explanation
Correct Answer: A
Alveoli are tiny air sacs in the lungs where oxygen and carbon dioxide are exchanged between the air and blood.
Q9
Hard
What is the primary factor that drives the movement of oxygen from the alveoli to the blood?
A. Concentration gradient
B. Active transport
C. Diffusion pressure
D. Ventilation rate
Show Answer & Explanation
Correct Answer: A
Oxygen moves from an area of higher concentration in the alveoli to lower concentration in the blood due to diffusion.
Q10
Hard
Which of the following statements regarding the respiratory system is incorrect?
A. The trachea is reinforced with cartilage.
B. The diaphragm is a skeletal muscle.
C. Gas exchange occurs mainly in the bronchi.
D. The lungs are enclosed by pleura.
Show Answer & Explanation
Correct Answer: C
Gas exchange primarily occurs in the alveoli, not in the bronchi.

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Breathing and Exchange of Gases — Class 11 Biology Practice Questions Online

This page contains 2297 practice MCQs for the chapter Breathing and Exchange of Gases in Class 11 Biology. The questions are organized by difficulty — 672 easy, 1152 medium, 473 hard — so you can choose the right level for your preparation.

Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 4 topics, giving you comprehensive coverage of the entire chapter.