Phospholipids are found in all bacteria, and in the cells of all plants and animals. They are most plentiful in sperm, eggs, embryos, and brain cells. A molecule of phospholipid contains a molecule of glycerol, a phosphate ion, and two molecules of fatty acid. Most phospholipids also have a nitrogen compound. Some contain inositol, a substance found in vitamin B complex.
Steroids make up an important part of living things.
Cholesterol, a substance found in the membranes of animal cells, is a steroid. Yeasts and other fungi and the seeds of higher plants also contain steroids. Quinton R. Rogers, Ph.D., Professor of Physiological Chemistry, Univ. of California, Davis. How to cite this article.