GENERAL HISTOLOGY

Detailed explanation-1: -The cell membrane is composed mainly of phospholipids, which consist of fatty acids and alcohol. The phospholipids in the cell membrane are arranged in two layers, called a phospholipid bilayer.

Detailed explanation-2: -Like all other cellular membranes, the plasma membrane consists of both lipids and proteins. The fundamental structure of the membrane is the phospholipid bilayer, which forms a stable barrier between two aqueous compartments.

Detailed explanation-3: -In water, phospholipids spontaneously form a double layer called a lipid bilayer in which the hydrophobic tails of phospholipid molecules are sandwiched between two layers of hydrophilic heads (see figure below).

Detailed explanation-4: -The plasma membrane is primarily composed of phospholipids arranged in a bilayer, with the hydrophobic tails on the interior of the membrane, and the hydrophilic heads pointing outwards.

Detailed explanation-5: -Only small uncharged molecules can diffuse freely through phospholipid bilayers (Figure 2.49). Small nonpolar molecules, such as O2 and CO2, are soluble in the lipid bilayer and therefore can readily cross cell membranes.