Question

Which statement is incorrect for ion-channels?

• A. They are protein
• B. Movement through them is simple diffusion
• C. Movement through them is from high to low concentration
• D. All ions pass through the same type of channel

Answer 1

The correct option is D All ions pass through the same type of channel

Ion channels are special proteins through which ions flow along the concentration gradient. These channels are important, because the membrane is made up of bilayer of lipids and will not allow transport of water soluble ions. However lipid soluble components can dissolve in membrane lipids and can be transported across the membrane without special carrier or transport proteins.
But all ions cannot pass through same transport protein because volume of each ion will be different. There are different transport proteins for transport of different ions.