Chapter Exam

Chapter 14: Breathing and Exchange of Gases — Online MCQ Test

Q: Which structure is the main site of exchange of respiratory gases in humans?

Answer: C. Alveoli — Alveoli have thin walls and a dense capillary network, making them the primary site for gas exchange.

Q: The normal respiratory rate in an adult human at rest is approximately:

Answer: B. 12-16 breaths per minute — An adult at rest typically breathes about 12-16 times per minute.

Q: Which of the following is NOT a component of the human respiratory system?

Answer: D. Nephrons — Nephrons are the functional units of the kidney, not the respiratory system.

Q: A person holding breath for some time experiences an urge to breathe mainly due to increased:

Answer: B. Carbon dioxide concentration in blood — Rising carbon dioxide levels stimulate the respiratory center and trigger the urge to breathe.

BIOLOGY · CLASS 11 FIRST PUC · Karnataka State Board

Practice Chapter 14: Breathing and Exchange of Gases with a free chapter-wise online MCQ test for Karnataka State Board CLASS 11 FIRST PUC BIOLOGY. This chapter covers: Respiration Lungs Alveoli Breathing Gas Exchange Oxygen Carbon Dioxide Respiratory System Ventilation Hemoglobin. AI-generated questions from basic to board-exam level, with instant results and explanations.

Questions

20m

Time Limit

Attempts Left

10 random questions from this chapter (mixed difficulty)
Questions you've seen before won't repeat until the pool resets
You have 20 minutes — exam auto-submits when time is up
Maximum 3 attempts per chapter
Results and explanations shown immediately after submission

New here? Register free — includes 3 free chapter exams.

Chapter 14: Breathing and Exchange of Gases — Important Questions & Answers (FAQ)

Frequently asked questions from Karnataka State Board CLASS 11 FIRST PUC BIOLOGY — Chapter 14: Breathing and Exchange of Gases, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which structure is the main site of exchange of respiratory gases in humans?

A. Trachea
B. Bronchi
C. Alveoli ✓
D. Diaphragm

Answer: C. Alveoli
Alveoli have thin walls and a dense capillary network, making them the primary site for gas exchange.

The normal respiratory rate in an adult human at rest is approximately:

A. 8-10 breaths per minute
B. 12-16 breaths per minute ✓
C. 20-24 breaths per minute
D. 30-35 breaths per minute

Answer: B. 12-16 breaths per minute
An adult at rest typically breathes about 12-16 times per minute.

Which of the following is NOT a component of the human respiratory system?

A. Nasal cavity
B. Trachea
C. Alveoli
D. Nephrons ✓

Answer: D. Nephrons
Nephrons are the functional units of the kidney, not the respiratory system.

A person holding breath for some time experiences an urge to breathe mainly due to increased:

A. Oxygen concentration in blood
B. Carbon dioxide concentration in blood ✓
C. Hemoglobin count
D. Blood glucose level

Answer: B. Carbon dioxide concentration in blood
Rising carbon dioxide levels stimulate the respiratory center and trigger the urge to breathe.

Which of the following is the correct reason for the efficiency of gas exchange in alveoli?

A. Thick epithelial lining and low capillary supply
B. Very small surface area and high diffusion distance
C. Large surface area, thin membrane, and rich blood supply ✓
D. Absence of moisture on alveolar surface

Answer: C. Large surface area, thin membrane, and rich blood supply
Alveoli are adapted for gas exchange by having a large surface area, thin walls, and extensive blood supply.