Membrane proteins are asymmetrically distributed according to the function of the membrane and its lipid composition.Which statement about peripheral membrane proteins is true?
A) They do not contain any hydrophilic regions.
B) They are embedded in the phospholipid bilayer.
C) They are able to move freely within the plasma membrane.
D) Their charged regions interact with other proteins or with phospholipids.
E) Their hydrophobic side chains interact with the lipid bilayer.

Question

Quizplus · Accepted Answer

Peripheral membrane proteins are not embedded within the phospholipid bilayer but rather interact with the membrane indirectly, through electrostatic interactions with the polar head groups of phospholipids or with other membrane-associated proteins. This interaction occurs through the charged regions of the protein, which are hydrophilic and therefore interact with the aqueous environment of the membrane. These charged regions may also interact with other proteins or with phospholipids, enabling the protein to perform its specific function. The hydrophobic side chains of peripheral membrane proteins do not interact with the lipid bilayer as extensively as integral membrane proteins but may be partially embedded in the hydrocarbon chains of phospholipids. Peripheral membrane proteins are generally less tightly associated with the membrane than integral membrane proteins and can be more easily detached with mild detergents or changes in pH or salt concentration. They may also be more mobile within the membrane, as they do not have to move in concert with the lipid bilayer.

Membrane Proteins Are Asymmetrically Distributed According to the Function of the Membrane