Question

In contact with water, phospholipids produce

• A. Monolayer
• B. Bilayer
• C. Trilayer
• D. Emulsion

Answer 1

The correct option is B Bilayer

The phospholipids are composed of a molecule of glycerol or other alcohol having a phosphate group joined to one of its outer -OH groups , two fatty acid molecules linked to other -OH groups and a nitrogen containing base bound to the phosphate group. Thus it has a strongly non-polar and hydrophobic tail consisting of fatty acid chains and a polar and hydrophilic head comprising a negatively charged phosphate group and a positively charged abse. Because of this dual solubility the phospholipids are called amphiphatic lipids. Due to this property, a phospholipid placed at the surface of water forms two molecules thick layer called lipid bilayer. The non-polar fatty acid chains of the two layers associate together in the hydrophobic interior of bilayer and their phosphate base groups face the surrounding water molecules. Such lipid bilayers are the basic components of cellular membranes.

Thus, the correct answer is option B.