Answer:
Phospholipids
Explanation:
Phospholipid bilayer is one of the components of the plasma membrane, and is made up of glycerol, two fatty acid tails and a phosphate head group. The head of the layer containing phosphate group is water-loving i.e. hydrophilic, hence, it faces outward attracted to intracellular and extracellular fluid while the tail consisting of two fatty acids is hydrophobic (water-fearing) and hence, faces inward to avoid water.
This property of the phospholipid bilayer is said to be AMPHIPATHIC. This amphipathic nature of the phospholipid component confers semi-permeability upon the plasma membrane as it serves as a chemical barrier, allowing only substances that are small in size and non-polar to move across the membrane without energy (passively).
