In the plasma membrane, the phospholipid heads
A) are hydrophilic and face outward toward the aqueous solution on both sides of the membrane.
B) are hydrophilic and face inward, shielded from water.
C) are hydrophobic and face outward toward the aqueous solution on both sides of the membrane.
D) are hydrophobic and face inward, shielded from water.

Question

Quizplus · Accepted Answer

The phospholipid heads are hydrophilic, containing a phosphate group that can interact with water molecules. Therefore, they face outward toward the aqueous solution on both sides of the membrane, creating a hydrophilic region. The tails, on the other hand, are hydrophobic and face inward, forming a non-polar region of the membrane. This arrangement allows the plasma membrane to be selectively permeable, controlling the movement of molecules in and out of the cell.

In the Plasma Membrane, the Phospholipid Heads