What is Gas Exchange?
Gas exchange is the process of diffusion(facilitated diffusion) in which oxygen and carbon dioxide are exchanged across specialised membranes. It is a biological process which allows the organism to obtain oxygen from their specific environment and to release carbon dioxide, a gas which is a product of the respiration process. Therefore, gas exchange is essential for an organism to be alive.
What are the Basic Requirements of Efficient Gas Exchange?
All living organisms must have a moist, thin surface and a large 'Surface Area : Volume' ratio to maintain and maximise diffusion efficiency.
Moist
The surface must be moist in order to allow oxygen to dissolve into water. This is to allow the oxygen to diffuse through the cell membrane through the process of diffusion, which can only happen when there is a concentration gradient.
Thin
By having a thin gas exchange surface which is often one cell thick, it minimises the distance that the gases must diffuse through, thus improving the rate of gas exchange.
Large 'S.A : VOL' Ratio
To make sure enough oxygen is diffused in a certain time frame to keep the organism alive, a larger surface area in relation to the size of the organism is required. This is because the rate of oxygen diffusing also relies on how big the gas exchange surface is, in relation to it's size.
Moist
The surface must be moist in order to allow oxygen to dissolve into water. This is to allow the oxygen to diffuse through the cell membrane through the process of diffusion, which can only happen when there is a concentration gradient.
Thin
By having a thin gas exchange surface which is often one cell thick, it minimises the distance that the gases must diffuse through, thus improving the rate of gas exchange.
Large 'S.A : VOL' Ratio
To make sure enough oxygen is diffused in a certain time frame to keep the organism alive, a larger surface area in relation to the size of the organism is required. This is because the rate of oxygen diffusing also relies on how big the gas exchange surface is, in relation to it's size.