There are several key differences between plant and animal cells, such as cell wall structure, presence or absence of plastids, lysosomes and centrioles and shape of vacuoles. These characteristics are the primary and most distinct differences between plant and animal cells. However, they only exist in organisms classified as eukaryotic, and occur primarily in central organelles.
Cell wall structure varies considerably between plant and animal cells. In plant cells, walls have shape but lack a clearly defined and rigid structure; biologists refer to this as having nearly-present walls. Animal cells, on the other hand, have no cell walls present outside their cell membranes. In plant cells, plastids are located in the cytoplasm while animal cells lack plastids. Most animal cells contain lysosomes, which are located primarily in their cytoplasms. Plant cells do not typically have lysosomes; if they do, those structures are also located in their cytoplasms. Organelles called centrioles occur in some plant cells, but are only found in cells of lower plant varieties. Centrioles are found in all animal cells, however. The last primary difference between plant and animal cells is that all plant cells contain structures called vacuoles, which are filled with gel-like cell sap. Some animal cells contain vacuoles, too; if present, those vacuoles are temporary or small and contractile.