1 A computer file format for STereoLithography, or Standard Tessellation Language. 2  It describes a physical space mathematically as a series of small triangles using a three-dimensional coordinate system, and is widely used in dentistry.
Phospholipids consist of a polar molecule, a phosphate group, a glycerol unit and two fatty acids. They are found in cell membranes, which enclose the cytoplasm and other parts of a cell. Steroids include cholesterol, cortisone and sex hormones, such as estrogen, testosterone and progesterone. They have a carbon backbone that contains four fused ring-like structures.
The phospholipid bilayer which the cell membrane is an example of, is composed of various cholesterol, phospholipids, glycolipids, blagoscony and proteins.