These chloroplasts are known as secondary plastids. There are many lines of evidence that mitochondria and plastids including chloroplasts arose from bacteria. All dinoflagellates contain red algal plastids or remnant (nonphotosynthetic) organelles of red algal origin. Myosin XI directs the movement of organelles such as plastids and mitochondria in plant cells. Some retain plastids, but not chloroplasts, while others have lost plastids entirely. Proteinoplasts belong to a broad category of organelles known as plastids. The mitochondria and the plastids of the diatom somehow remain functional. Later endosymbiosis led to the spread of plastids in some lineages. They are non-pigmented, in contrast to other plastids such as the chloroplast. In red algae, floridean starch is synthesized and stored outside the plastids in the cytosol. Such loss is also rarely observed in other plastids and prokaryotes. There have been a number of discoveries of PPR proteins in both plastids and mitochondria. Unlike other apicomplexans, "C. parvum" has no genes in its plastids or mitochondria. Many plastids, particularly those responsible for photosynthesis, possess numerous internal membrane layers. All these primary plastids are surrounded by two membranes.