Revision Notes For For Class 11 Biology Chapter 17 Breathing And Exchange Of Gases

Breathing is the process of inhaling or breathing in the air into the lungs and exhaling or breathing out the air from the lungs. The process of inhaling and exhaling air is termed as Respiration. All living organisms, from a single bacterial cell to a blue whale, undergo respiration and it is the most important life process as it helps in the production of energy for the different metabolic activities. The movement of air during the process of respiration facilitate gaseous exchange within the environment.

In humans, the gaseous exchange or exchange of gases occurs in the Alveoli, hence it is called the primary sites for the exchange of gases. Here the gaseous exchange of oxygen and carbon dioxide occurs by the simple diffusion process. The exchange of gases also occurs between blood cells and the tissues.

CBSE Notes for Class 11 Biology Chapter 17 Breathing and Exchange of Gases

For more information about the Breathing and Exchange of Gases, click on the below-mentioned links.

Exchange Of Gases Respiration
The Human Respiratory System Respiratory System

Frequently asked Questions on CBSE Class 11 Biology Notes Chapter 17: Breathing and Exchange of Gases


What are ‘Alveoli’?

The pouch-like air-sacs at the ends of the smallest bronchioles are called alveoli. The walls of alveoli are very thin and they are surrounded by very thin blood capillaries.


What is meant by the ‘diffusion process’?

Process resulting from random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration.


What are the functions of the lungs?

The main function of the lungs is the process of gas exchange called respiration (or breathing). In respiration, oxygen from incoming air enters the blood, and carbon dioxide, a waste gas from the metabolism, leaves the blood.


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