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| cell | a membrane-bound structure that is the basic unit of life |
| cell membrane | the lipid bilayer that forms the outer boundary of a cell |
| cell theory | the theory that all living things are made up of cells, that cells are the basic units of organisms, and that cells come only from existing cells |
| eukaryote | a cell that contains a nucleus and membrane-bound organelles |
| nucleus (in a eukaryotic cell) | the organelle that contains most of the DNA and controls most of the cell's activities |
| organelle | one of several formed bodies with a specialized function that is suspended in the cytoplasm and found in eukaryotic cells |
| prokaryote | a unicellular organism that LACKS a nucleus and membrane-bound organelles |
| cell wall | a rigid structure that surrounds the cells of plants, fungi, many protists, and most bacteria |
| chloroplast | a plastid containing chlorophyll; the site of photosynthesis |
| cilium | a short, hairlike organelle that extends from a cell and functions in locomotion or in the movement of substances across the cell surface |
| cytoplasm | the region of a cell between the cell membrane and the nucleus |
| cytoskeleton | a network of long protein strands in the cytosol that helps maintain the shape and size of a eukaryotic cell |
| chromatin | the DNA and proteins in the nucleus of a nondividng cell |
| chromosome | DNA and protein in a coiled, rod-shaped form that occurs during cell division |
| cytosol | the gelatinlike aqueous fluid that bathes the organelles on th inside of the cell membrane |
| endoplasmic reticulum | a system of membranous tubules and sacs in eukaryotic cells that functions as a path along which molecules move from one part of the cell to another |
| flagellum | a hairlike structure made up of microtubules that function in locomotion |
| fluid mosaic model | a model of cell membrane structure representing the dynamic nature of membrane lipids and proteins |
| golgi apparatus | a system of membranes in eukaryotic cells that modifies proteins for export by the cell |
| integral protein | a protein imbedded in the bilayer of the cell membrane |
| lysosome | an organelle containing digestive enzymes, existing primarily in animal cells |
| microfilament | a polymer chain of the protein actin; the smallest strand in the cytoskeleton |
| microtubule | a hollow tube of protein that constitutes the largest strand in the cytoskeleton |
| mitochondrion | the organelle that is the site of aerobic respiration in eukarytoic cells (glucose is converted to ATP) |
| nuclear envelope | a double membrane that surrounds the nucleus of a eukaryotic cell |
| nuclear matrix | nucleoplasm; the nuclear skeleton, a shape-maintaining protein |
| nuclear pore | a small hole in the nuclear envelope through which substances pass between the nucleus and the cytoplasm |
| nucleolus | the structure in which ribosomes are synthesized and partially assembled; found in most nuclei |
| peripheral protein | a protein attached to the interior or exterior surface of the cell membrane |
| ribosome | an organelle that functions in the synthesis of proteins |
| rough endoplasmic reticulum | the portion of the ER that contains attached ribosomes and makes proteins |
| selectively permeable membrane | a membrane that keeps out some molecules but allows others to pass through |
| smooth endoplasmic reticulum | the portion of the endoplasmic reticulum that LACKS attached ribosomes; makes lipids and detoxifies drugs |
| spindle fiber | one of the microtubules that extend across a dividing eukaryotic cell; assisits in the movement of chromosomes |
| thylakoid | a flattened, membranous sac inside a chloroplast; contains most of the components involved in the light reactions of photosynthesis |
| vacuole | a fluid-filled organele that stores enzymes or metabolic wastes in a plant cell |
| colonial organism | a collection of genetically identical cells that live together in a closely connected group |
| organ | several types of body tissues that perform together a specific function |
| organ system | a group of organs that interact to perform a set of related tasks |
| tissue | in most multicellular organisms, a group of similar cells that carry out a common function |
