Term | Definition |
Cell Theory | the theory that states that all living things are made up of cells, that cells are the basic units of organisms, that each cell in a multicellular organism has a specific job, and that cells come only from existing cells |
Cytoplasm | the material or protoplasm within a living cell, excluding the nucleus. |
Organelle | a specialized subunit within a cell that has a specific function. |
Prokaryotic Cell | A microscopic single-celled organism which has neither a distinct nucleus with a membrane nor other specialized organelles, including the bacteria and cyanobacteria. |
Eukaryotic Cell | An organism whose cells contain a nucleus surrounded by a membrane and whose DNA is bound together by proteins (histones) into chromosomes |
Cytoskeleton | the cytoplasmic network of protein filaments that plays an essential role in cell movement, shape, and division |
Nucleus | physical science, an atom's central region, which is made up of protons and neutrons |
Endoplasmic reticulum | a system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids |
Ribosome | a cell organelle composed of RNA and protein; the site of protein synthesis |
Golgi apparatus | a cell organelle that helps make and package materials to be transported out of the cell |
Vesicle | a small cavity or sac that contains materials in a eukaryotic cell; forms when part of the cell membrane surrounds the materials to be taken into the cell or transported within the cell |
Mitochondrion | in eukaryotic cells, the cell organelle that is surrounded by two membranes and that is the site of cellular respiration, which produces ATP |
Vacuole | a fluid-filled vesicle found in the cytoplasm of plant cells or protozoans |
Lysosome | a cell organelle that contains digestive enzymes |
Centriole | an organelle that is active during mitosis |
Cell wall | a rigid structure that surrounds the cell membrane and provides support to the cell |
Chloroplast | an organelle found in plant and algae cells where photosynthesis occurs |
Cell membrane | a phospholipid layer that covers a cell’s surface and acts as a barrier between the inside of a cell and the cell’s environment |
Phospholipid | a lipid that contains phosphorus and that is a structural component in cell membranes |
Fluid mosaic model | |
Selective permealbility | |
Receptor | a specialized sensory nerve that responds to specific types of stimuli |
Passive transport | the movement of substances across a cell membrane without the use of energy by the cell |
Diffusion | the movement of particles from regions of higher density to regions of lower density |
Concentration gradient | a difference in the concentration of a substance across a distance |
Osmosis | the diffusion of water or another solvent from a more dilute solution (of a solute) to a more concentrated solution (of the solute) through a membrane that is permeable to the solvent |
Isotonic | a solution whose solute concentration is equal to the solute concentration inside a cell |
Hypertonic | describes a solution whose solute concentration is higher than the solute concentration inside a cell |
Hypotonic | describes a solution whose solute concentration is lower than the solute concentration inside a cell |
Facilitated diffusion | the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins |
Active transport | the movement of chemical substances, usually across the cell membrane, against a concentration gradient; requires cells to use energy |
Endocytosis | he process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the particle into the cell |
Phagocytosis | the process by which a cell engulfs large particles or whole cells, either as a defense mechanism or as a means to obtain food |
Exocytosis | the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out |