Which of the following is(are) considered the most important component(s) of pulmonary surfactant?
I. Dipalmitoyl phosphatidylcholine
II. Phosphatidylglycerine
III. Phosphatidylinositol
IV. Sphingomyelin

Question

Quizplus · Accepted Answer

Surfactant composition is fairly constant among mammalian species. Surfactant is composed of approximately 90% lipids (of which 80% to 85% are phospholipids) and approximately 10% proteins (see Table 14-1 in the textbook). Phosphatidylcholine (PC) is the most abundant phospholipid (75% to 80%) and is mostly saturated (40% to 55%) in the form of dipalmitoyl phosphatidylcholine (DPPC). DPPC is the most important surfactant component in reducing surface tension; it consists of two molecules of palmitic acid and one molecule of phosphatidylcholine attached to a glycerol backbone. DPPC has a hydrophobic end (fatty acids) and a hydrophilic end (nitrogenous base) and aligns itself in the air-liquid interface with the hydrophobic end toward the gas phase and the hydrophilic end toward the liquid phase.

Which of the Following Is(are) Considered the Most Important Component(s)