Physiology MCQ Answer 06

• The plasma membrane defines the boundary of the cell and serves to contain and concentrate enzymes and other macromolecule constituents.
  
• The plasma membrane is composed of amphipathic molecules, mainly phospholipids and proteins that contain distinct regions that are either insoluble in water (hydrophobic) or soluble in water (hydrophilic).
• The plasma membrane forms a continuous barrier between the aqueous extracellular and intracellular fluids.
  
• Transport proteins in the membrane act as regulated channels or transporters to maintain the intracellular ionic milieu that is clearly different from the extracellular milieu.
• In some cells, membrane proteins are diversified such as in nerve cells where the ion channels are highly voltage-dependent, providing the basis for information transmission in the form of electrical impulses.
  
• Most plasma membrane proteins extend externally and bear carbohydrate moieties primarily as oligosaccharide chains that contribute to the cell coat or glycocalyx.

Category: Physiology MCQs