<Li> A cell wall composed of cellulose and hemicelluloses, pectin and in many cases lignin, is secreted by the protoplast on the outside of the cell membrane . This contrasts with the cell walls of fungi, which are made of chitin, and of bacteria, which are made of peptidoglycan . Cell walls perform many essential functions: they provide shape to form the tissue and organs of the plant, and play an important role in intercellular communication and plant - microbe interactions . </Li> <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>

What is the meaning of the plant cell