AP BIOLOGY

Detailed explanation-1: -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-2: -Phospholipids, arranged in a bilayer, make up the basic fabric of the plasma membrane. They are well-suited for this role because they are amphipathic, meaning that they have both hydrophilic and hydrophobic regions. Chemical structure of a phospholipid, showing the hydrophilic head and hydrophobic tails.

Detailed explanation-3: -The phosphate group is the negatively-charged polar head, which is hydrophilic. The fatty acid chains are the uncharged, nonpolar tails, which are hydrophobic.

Detailed explanation-4: -The hydrophilic heads attract water into the membrane and are then propelled away by the hydrophobic tails. Lastly the water is pulled across the membrane by the 2nd hydrophilic head. Hydrophilic means water loving and attracts water molecules while hydrophobic means water fearing and pushes water molecules away.

Detailed explanation-5: -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).