Question

How is facilitated diffusion different from active transport?

Answer 1

Facilitated diffusion involves movement of solutes along the concentration gradients and the passage of molecules is mediated by transport protein (carriers and channels) and is selective in nature.
Active transport occurs against the concentration gradient and is mediated by carrier proteins. Metabolic energy is used to move ions or molecules against a concentration gradient.

Complete answer:

| Facilitated Diffusion| Active Transport
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Definition| The process facilitating the movement of nutrients across the membrane by carrier or channel proteins in the membrane without using energy.| The movement of nutrients across the cell membrane against the concentration gradient by utilizing the energy.
Process| Passive| Active
Occurrence| Occurs along the concentration gradient.| Occurs against the concentration gradient.
Use of Energy| Do not utilize energy.| Utilizes energy
Proteins Involved | Gated ion channels| Sodium-Potassium pump, Sodium/Glucose symporter, Transmembrane ATPases etc.
Termination| Facilitated diffusion stops when the equilibrium is reached.| Causes accumulation of nutrients inside the cells, it does not stop though the equilibrium is reached.
Examples| Glucose transportation through membranes of cells of the alimentary canal towards endothelial cells lining blood capillaries, ion movements in excitatory cells etc.| The uptake of glucose in the intestine in humans, the uptake of mineral ions into the root hair cells of plants.

Note: The rate of transport of the molecule across the membrane is far greater in facilitated diffusion as compared to simple diffusion. Facilitated diffusion allows polar and charged molecules, such as carbohydrates, amino acids, nucleosides and ions to cross the plasma membrane.
In active transport metabolic energy is used to move ions or molecules against a concentration gradient. Active transport results in the accumulation of solute on one side of the membrane.