Eukaryotic cell structure. Cutaway computer illustration showing the organelles and structure of the outer layers of a typical eukaryotic cell with a cell wall. A eukaryote is any organism whose cells contain a nucleus and other organelles enclosed within membranes. Cell walls are found in the cells of plants, fungi and most chromalveolates. The structure of the outer layers of the cell is shown (inset, from top to bottom): Middle lamella; primary cell wall - consisting of pectin, soluble proteins, hemicellulose and cellulose microfibres; plasma membrane.