ABSTRACT
Cells provide structure and function for all living things, from microorganisms to humans. Scientists consider them the smallest form of life. Cells house the biological machinery that makes the proteins, chemicals, and signals responsible for everything that happens inside the bodies. Cells come in different shapes—round, flat, long, star-like, cubed, and even shapeless. Most cells are colorless and see-through. The size of a cell also varies. When putting cells into categories, scientists can tell eukaryotic cells apart from prokaryotic cells because they look different. Eukaryotic cells make up animals, plants, fungi, and some single-celled organisms. Many types of cells can move. Single-celled organisms move to find food. And even cells inside multicellular organisms may need to get around. Cell biologists rely on an array of tools to peer into the body and examine cells. One cell divides into two in a process called mitosis. Mitosis produces two genetically identical "daughter" cells from a single parent cell.
