Monday, 11 December 2017

Diffusion and its significance


Movement of ions or molecules from its region of higher concentration to its region of lower concentration known as diffusion. It is material transport phenomena by the motion of atoms. It is a biological process. Example: Perfumed is sprayed in one corner of room but it can be smelled in another corner of room. This is because of diffusion by which perfume molecules reaches to another corner of room. The concentration of  molecules of perfume was higher in one corner after which molecules diffuses to another corner.


Diffusion is based on concentration gradient.
Concentration gradient
Concentration gradient is the gradual difference in concentration of dissolved substance in two different regions in which one region is of high density and another region is of low density.

Types of diffusion

Diffusion is of three types
1.Simple diffusion
2.Channel diffusion
3.Facilitated diffusion

1. Simple diffusion
In this process some very small nonpolar molecules can directly pass through the cell membrane like oxygen and carbon dioxide molecules.

2. Channel diffusion
Some molecules needs help to move through the cell membrane due to their polarity.
So protein molecules are embedded in cell membrane for the help these molecules to pass through the  cell membrane, where molecules move down the concentration gradient through an open protein pore.

3. Facilitated diffusion
Carrier proteins are involved in this to transport the molecules.
These carrier proteins only allows the specific molecules to pass through the cell membrane.
When all carrier proteins are occupied with particular molecule  the a saturation point is reached.

Diffusion favouring factors
Different factors favoring the diffusion are:
Distance: In short distance diffusion is better.
Concentration gradient: Diffusion is better when concentration is more.
Size: Smaller size better diffusion.
Surface area: Larger the surface area better diffusion.
Temperature: High temperature favors the diffusion because kinetic energy of molecules is more at high temperature which helps the molecules to move easily.

Significance of diffusion
Diffusion helps plants in many different ways: gas
It helps plants to remove their waste products like oxygen which is waste product of photosynthesis.
It helps in gaseous exchange which makes respiration easy for plants and CO2 gas diffuses from air to leaves through the stomatal pores.


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