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biology cell
| Term | Definition |
|---|---|
| cell | basic unit of all forms of life |
| cell theory | fundamental concept of biology that states that all living things are composed of cells; that cells are the basic units of structure and function in living things; and that new cells are produced from existing cells |
| cell membrane | thin, flexible barrier that surrounds all cells; regulates what enters and leaves the cell |
| nucleus | the center of an atom, which contains the protons and neutrons |
| eukaryote | organism whose cells contain a nucleus |
| prokaryote | unicellular organism that lacks a nucleus |
| cytoplasm | fluid portion of the cell outside the nucleus |
| organelle | specialized structure that performs important cellular functions within a eukaryotic cell |
| ribosome | cell organelle consisting of RNA and protein found throughout the cytoplasm in a cell; the site of protein synthesis |
| endoplasmic reticulum | internal membrane system found in eukaryotic cells; place where lipid components of the cell membrane are assembled |
| Golgi apparatus | organelle in cells that modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell |
| vacuole | cell organelle that stores materials such as water, salts, proteins, and carbohydrates |
| lysosome | cell organelle that breaks down lipids, carbohydrates, and proteins into small molecules that can used by the rest of the cell |
| cell wall | strong, supporting layer around the cell membrane in some cells |
| cytoskeleton | network of protein filaments in a eukaryotic cell that gives the cell its shape and internal organization and is involved in movement |
| chloroplast | organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy |
| mitochondrion | cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use |
| lipid bilayer | flexible double-layered sheet that makes up the cell membrane and forms a barrier between the cell and its surroundings |
| selectively permeable | property of biological membranes that allows some substances to pass across it while others cannot; also called semipermeable membrane |