EVERYDAY SCIENCE

Detailed explanation-1: -The fundamental building blocks of all cell membranes are phospholipids, which are amphipathic molecules, consisting of two hydrophobic fatty acid chains linked to a phosphate-containing hydrophilic head group (see Figure 2.7).

Detailed explanation-2: -With few exceptions, cellular membranes-including plasma membranes and internal membranes-are made of glycerophospholipids, molecules composed of glycerol, a phosphate group, and two fatty acid chains. Glycerol is a three-carbon molecule that functions as the backbone of these membrane lipids.

Detailed explanation-3: -Part of the cell membrane is a phospholipid bilayer, made of two layers of phospholipid molecules. However, the cell membrane also contains other macromolecules like membrane proteins, and carbohydrates. Therefore, we can say that the cell membrane is made of a phospholipid bilayer, but it is not only made of it.

Detailed explanation-4: -Bulk membrane lipid biogenesis in primary cells largely occurs in the endomembrane compartment, which includes the domains of the ER and Golgi apparatus. Specialized phospholipids are synthesized in mitochondria or perosixomes.