In: Biology
Which most effectively describes the relationship between carrier and channel proteins?
(Select all that apply.)
A) Carrier proteins are passive transport mechanisms, but channel proteins can be either active or passive.
B) Carrier proteins are active transport mechanisms, but channel proteins can be either active or passive.
C) Channel proteins are active transport mechanisms, but carrier proteins can be either active or passive.
D) Channel proteins are passive transport mechanisms, but carrier proteins can be either active or passive.
D is the correct answer.
Explaination : As compared to the non-polar molecules (like O and CO) and small polar uncharged molecules which can effectively diffuse through the lipid bilayer along their conceconcentr gradient, charged molecules are highly impermeable. Cell utilizes specific membrane proteins for the transport of such charged molecules, which are classiclassinto two categories : Channels and Carriers
Carrier proteins usually undergoes a conformational change in their tertiary structure upon the binding of the solute to be transported.. It could either facilitate passive transport of the solute along the concentration gradient or it could be coupled with an energy source like ATP or an ion gradient for the active transport of the solute against its concentration gradient.
Channel proteins on the other hand, function as aqueous pores, which interact with the ions only weakly, thus allowing specific ions to pass passively along their concentration gradient across the membrane.