Facilitated Transport in Plants: It is also known as Facilitated diffusion. Molecules in facilitated diffusion diffuse across the plasma membrane with aid from the membrane proteins such as the carrier and channels. A concentration gradient is seen in these molecules for it has the potential for diffusing into cells by moving down them. But, as they are polar or charged, it cannot cross the phospholipid part of the membrane with no assistance. The facilitated transport proteins protect such molecules from the hydrophobic core of the membrane rendering a path through which it can cross. Carrier proteins and channels are the two broad classes of facilitated transport proteins.

Importance of Facilitated Transport in Plants

• Biological membranes basically are hydrophobic in nature.
• Water soluble molecules like glucose, sodium ions and chloride ions cannot pass through the membrane as the lipids make it hydrophobic in nature.
• Transport of such substances is facilitated by transport proteins. These proteins are embedded in the bilipid layer. They provide the binding site for molecules to be transported.

Factors Affecting Facilitated Transport in Plants

Brownian motion is the force behind the diffusion of fluids. The main factors affecting the process of facilitated diffusion are:

• Temperature- As the temperature increases, the movement of the molecules increases due to an increase in energy.

• Concentration- The movement of the molecules takes place from the region of higher concentration to lower concentration.

• Diffusion Distance- The diffusion rate is faster through smaller distance than through the larger distance. For eg., gas diffuses much faster through a thin wall than through a thick wall.

• Size of the molecules- The smaller molecules are lighter and hence diffuse faster than the larger molecules.

Examples of Facilitated Transport in Plants

• Glucose Transporter
• Aquaporins
• Ion Channels

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By Team Learning Mantras