According to fluid mosaic model plasma membrane is composed by

Phospholipids extrinsic proteins and intrinsic proteins plasma membrane consists of lipids (20 – 79%) proteins (20 – 70%) carbohydrates (1 – 5%) and water (20%) protein molecules occur at places both iriside (intrinsic proteins) and on outer side (extrinsic proteins) of the phosphoipid bilayer.