What are the differences between channel and carrier proteins?

Basis of Differentiation

Channel Protiens

Carrier Proteins

Definition 

Channel proteins are proteins that create hydrophilic holes in cell membranes, facilitating the transport of molecules down the concentration gradient.

Carrier proteins are integral proteins that transport chemicals across the membrane both down and up the concentration gradient.

Direction of Transport

Channel proteins transport substances only down a concentration gradient.

Carrier proteins transport substances both down and against the concentration gradient.

Energy Consumption

Channel proteins only transport ions and molecules down the concentration gradient, which does not require any energy. 

Carrier proteins only consume energy to transport substances against the concentration gradient. No energy is used to transport substances down the concentration gradient.

Type of Transportation

Active diffusion is the only type of transportation used. 

Both active and passive diffusion are used. 

Conformation 

The conformation of channel proteins remains fixed at all times and does not change even when transporting molecules. 

Carrier proteins flip between two conformations during the process of transporting molecules across the cell membrane. 

Mechanism

Channel proteins form hydrophilic pores through the membrane, which allow the target molecules or ions to pass through the membrane by diffusion, without consuming any energy and without any interaction with each other. 

Carrier proteins bind to target chemicals on one side of the membrane and alter their conformation so that the substances can be released on the other side of the membrane. 

Lipoproteins/ Glycoproteins

Channel proteins are lipoproteins.

Carrier proteins are glycoproteins

Where Synthesis Occurs

Channel proteins are synthesized in the rough endoplasmic reticulum.

Carrier proteins are synthesized in the free ribosomes in the cytoplasm. 

Type of Molecules That Are Transported

They only transport water-soluble molecules. 

They transport both water soluble and insoluble molecules. 

Rate of Transportation

Relatively fast

Much slower

Energy requirement

Channel proteins do not consume any energy as they only transport proteins down the concentration gradient.   

Carrier proteins only require energy when transporting molecules against the concentration gradient.

Types 

There are two types of channel proteins: Non-gated and Gated

There are three types of carrier proteins: Uniporters, Symporters, Antiporters

Examples

Examples of channel proteins include: Potassium, Chloride, Calcium, Sodium ion channels, Aquaporins

Examples of carrier proteins include: Sodium-potassium pump, Glucose-sodium cotransport, Glucose transporters, Valinomycin