Term | Definition |
cell theory | the major principles of this are: 1) all organisms are made of cells, 2) all existing cells are produced by other living cells, and 3) the cell is the most basic unit of life |
cytoplasm | a jellylike substance that contains dissolved molecular building blocks |
organelle | structures specialized to perform distinct processes within a cell |
prokaryotic cell | cells that do not have a nucleus or other membrane bound organelles |
eukaryotic cell | cells that do have a nucleus and other membrane bound organelles |
cytoskeleton | a network of proteins that is constantly changing to meet the needs of a cell |
nucleus | the storehouse for most of the genetic information (or DNA) in a cell |
endoplasmic reticulum | an interconnected network of then folded membranes |
ribosome | tiny organelles that link amino acids together to form proteins |
Golgi apparatus | closely layered stacks of membrane-enclosed spaces that process, sort, and deliver proteins |
vesicle | small membrane-bound sacs that divide some materials from the rest of the cytoplasm and transport these materials from place to place within the cell |
mitochondrion | the powerhouse of the cell; supplies energy to the cell |
vacuole | a fluid-filled sac used for the storage of materials needed by the cell |
lysosome | membrane-bound organelles that contain enzymes |
centriole | cylinder-shaped organelles made of short microtubules arranged in a circle |
cell wall | a rigid layer that gives protection, support, and shape to the cell (only present in plant cells) |
chloroplast | organelles that carry out photosynthesis |
cell membrane | the plasma membrane that forms a boundary between a cell and the outside environment and controls the passage of materials into and out of the cell |
phospholipid | a molecule composed of three basic part: a charged phosphate group, glycerol, and two fatty acid chains |
fluid mosaic model | a model that describes the arrangement of the molecules that make up a cell membrane |
selective permeability | the allowance of some but not all materials to cross |
receptor | a protein that detects a signal molecule and performs an action in response |
passive transport | the movement of molecules across a cell membrane without energy input from the cell |
diffusion | the movement of molecules in a fluid or gas from a region of higher concentration to a region of lower concentration |
concentration gradient | the difference in the concentration of a substance from one location to another |
osmosis | the process in which water molecules move across a semipermeable membrane from an area of higher water concentration to an area of lower water concentration |
isotonic | a type of solution that has the same concentration of dissolved particles as the cell |
hypertonic | a type of solution that has a higher concentration of dissolved particles than a cell |
hypotonic | a type of solution that has a lower concentration of dissolved particles than a cell |
facilitated diffusion | the diffusion of molecules across a membrane through transport proteins |
active transport | transport that drives molecules across a membrane from a region of lower concentration to a region of higher concentration |
endocytosis | the process of taking liquids or fairly large molecules into a cell by engulfing them in a membrane |
phagocytosis | a type of endocytosis in which the cell membrane engulfs large particles |
exocytosis | the release of substances out of a cell by the fusion of a vesicle with the membrane |