Why Gas Exchange

Gas exchange is the movement of respiratory gases across a membrane. It is the delivery of oxygen to the body, and the elimination of carbon dioxide from the body .The reason why gas exchange takes place because oxygen is one of the most essential requirements of life, without which organisms on Earth would not survive. Living organisms generate energy from food through the process of respiration. This allows humans and other organisms to perform their daily tasks. Oxygen is used in mitochondria to generate adenosine triphosphate (ATP) during respiration. Carbon dioxide is a product of this cellular metabolism. Carbon dioxide is a waste product and must be removed from our body much like trash must be taken out of the house.
Gas exchange mechanisms
Carbon dioxide is transported from the body to the air. Moving gases is called gas exchange. The gases move by diffusion from where they have a high concentration to where they have a low concentration. Oxygen diffuses from the air into the body and carbon dioxide diffuses from the body into the air .The percentage of oxygen availability in the air is 20% which is greater compared to the oxygen availability in the water which is only 1%
Gas exchange mechanisms need to be specific in order to make gas exchange process efficient. Requirements of gas exchange include:-
Moist Surface- Efficient gas exchange relies on a moist surface as oxygen must first dissolve into water before it can diffuse through a cell membrane.
Concentration Gradient- Cellular respiration ultimately relies on the diffusion of oxygen into the cell and carbon dioxide out of the cell. Diffusion is the net movement of particles down their concentration gradient. In order for oxygen to diffuse into the cell there must be a higher concentration outside the cell. Similarly, in order for carbon dioxide to diffuse out of the cell there must be a lower concentration of carbon dioxide surrounding the