AP BIOLOGY

Detailed explanation-1: -All of the lipid molecules in cell membranes are amphipathic (or amphiphilic)-that is, they have a hydrophilic (“water-loving”) or polar end and a hydrophobic (“water-fearing”) or nonpolar end. The most abundant membrane lipids are the phospholipids. These have a polar head group and two hydrophobic hydrocarbon tails.

Detailed explanation-2: -Each lipid molecule contains two parts; a head and a tail. The head is polar and hydrophilic ( Water loving) and the tail is non-polar and hydrophobic( Water hating).

Detailed explanation-3: -Lipid headgroups are substituents that attach to the glycerol, sphingosine, or cholesterol backbones of polar membrane lipids. Phospho-and glycolipids have headgroups linked to the backbone through a phosphodiester bond (Figure 1.2. 2). Understanding head group behavior is necessary for the study of membrane biology.

Detailed explanation-4: -1: A phospholipid consists of a head and a tail. The “head” of the molecule contains the phosphate group and is hydrophilic, meaning that it will dissolve in water. The “tail” of the molecule is made up of two fatty acids, which are hydrophobic and do not dissolve in water.

Detailed explanation-5: -Most lipids are non-polar (having no charged areas) or only slightly polar, with a very few charged areas. Water mixes with hydrophilic (water-loving) compounds by sticking to their charged groups. Since lipids lack charged groups, the water molecules have nothing to stick to and don’t mix with them.