AP BIOLOGY

Detailed explanation-1: -The phosphate group is the negatively-charged polar head, which is hydrophilic. The fatty acid chains are the uncharged, nonpolar tails, which are hydrophobic. Since the tails are hydrophobic, they face the inside, away from the water and meet in the inner region of the membrane.

Detailed explanation-2: -The heads (the phospho part) are polar while the tails (the lipid part) are non-polar. The heads, which form the outer and inner linings, are “hydrophilic” (water loving) while the tails that face the interior of the cell membrane are “hydrophobic” (water fearing).

Detailed explanation-3: -Polar lipids are amphiphilic lipids with a hydrophilic head and a hydrophobic tail. Polar lipids mainly include phospholipids and sphingolipids.

Detailed explanation-4: -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: -Phospholipids can be described as amphipathic ("amphi” means “both"), because they have this dual nature (part polar and part non-polar). This characteristic causes phospholipids to self-associate into large macromolecular complexes in an aqueous (watery) environment.