It's not always the same.
For a common description, it will contain cholesterol, proteins, carbohydrates, and phospholipids. However, when carbohydrates are attached to proteins or phospholipds, the proteins are called glycoproteins and the phospholipids are called glycolipids.
There's also something called the bilayer, wich has phospholipids with hydrophilic ends and hydrophobic ends. You could say there are two sets of the phospholipids when it comes to the bilayer. The hydrophobic ends of the phospholipids point towards each other, and the hydrophilic ends point away from each other (picture two fish facing opposite directions. The fins of the fish are pointing towards each other, but their front ends are facing opposite directions).