Cholesterol regulates the fluidity of the cell membrane.

Glycolipids extend from the cell membrane in the extracellular environment. They help to establish the identity of the cell as part of a particular tissue or organ.

Fatty acids are on the inner side of the layers of phospholipid molecules. This side has no electric charge, it is neutral, hydrophobic and water-insoluble.

Integral proteins are permanently attached to the cell membrane. Some span the entire membrane and function as gateways for the transport of specific substances.

Peripheral proteins are temporarily attached to the membrane, to facilitate interaction with the cell's environment, regulate cell signaling or other cellular events.

Phosphate groups are on the outside of the phospholipid bilayer. These molecules have an electric charge and are attracted to water (hydrophilic).