Both plant and animal cells are eukaryotic. Their cytoplasm contains membrane-bound organelles, such as the nucleus, endoplasmic reticulum, and mitochondria. However, they differ in their structure, mode of nutrition, and functions. Plant cells can range from 10 to 100 microns in size and are primarily supported by a cell wall and a large central vacuole. The water-filled vacuole stores nutrients and helps maintain turgor pressure to support the cell shape. In contrast, animal cells are smaller, measuring only 10 to 30 microns in size. They lack a cell wall and have numerous small vacuoles. Animal cells are supported internally by a network of protein filaments called the cytoskeleton. Both these cell types primarily differ in their nutritional requirements. While plant cells contain plastids, such as chloroplasts, that enable them to carry out photosynthesis and make their food; animal cells can only ingest nutrients from the outside. In animal cells, membrane-bound organelles called lysosomes function as sites for the breakdown of macromolecules. However, these organelles are rarely observed in plant cells. Whereas plant cells lack cilia and flagella, animal cells often have such cellular appendages that help in motility.