<Li> Specialized cell - to - cell communication pathways known as plasmodesmata, pores in the primary cell wall through which the plasmalemma and endoplasmic reticulum of adjacent cells are continuous . </Li> <Li> Plastids, the most notable being the chloroplast, which contains chlorophyll, a green - colored pigment that absorbs sunlight, and allows the plant to make its own food in the process known as photosynthesis . Other types of plastids are the amyloplasts, specialized for starch storage, elaioplasts specialized for fat storage, and chromoplasts specialized for synthesis and storage of pigments . As in mitochondria, which have a genome encoding 37 genes, plastids have their own genomes of about 100--120 unique genes and, it is presumed, arose as prokaryotic endosymbionts living in the cells of an early eukaryotic ancestor of the land plants and algae . </Li> <Li> Cell division by construction of a phragmoplast as a template for building a cell plate late in cytokinesis is characteristic of land plants and a few groups of algae, notably the Charophytes and the Chlorophyte Order Trentepohliales . </Li> <Li> The motile, free - swimming sperm of bryophytes and pteridophytes, cycads and Ginkgo are the only cells of land plants to have flagella similar to those in animal cells, but the conifers and flowering plants do not have motile sperm and lack both flagella and centrioles . </Li>

When is a cell categorized as a specialized cell