The mycelial and yeast phases differ in their morphology, biochemistry, and ultrastructure. There is substantial diversity in pyrenoid morphology and ultrastructure between algal species. It is not a good fixative when tissue ultrastructure must be preserved for electron microscopy. The plastids differ both in their pigmentation and in their ultrastructure. Their ultrastructure plays an important role in classifying eukaryotes. This is based on the pharyngeal jaw apparatus, sperm ultrastructure, and molecular evidence. Nanoscale structure in biology is often called ultrastructure. The group is characterized by the ultrastructure of the flagella. Features of ultrastructure are used industrially to control material properties and promote biocompatibility. Biopsy also allows early detection of cardiac injury by evaluating heart ultrastructure changes. Controlling ultrastructure has engineering uses for controlling the behavior of cells. Hydroxyapatite is a biomaterial used to interface medical devices directly to bone by ultrastructure. The nanostructure of biological specimens is referred to as ultrastructure. The initial classification of the pathogen as a chytrid was based on zoospore ultrastructure. The ultrastructure of the cuticles varies in different species.