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Cells
Biology
Term | Definition |
---|---|
Cell Theory | A theory in biology that states that the cell is the fundamental structure of all living beings, only produced by living cells, and the basic units of life. |
Cytoplasm | The substance surrounding the whole cell containing the organelles. |
Organelle | Any of a number of organized structures within a cell. |
Prokaryotic Cell | Only found in one celled organisms, they do not have a nucleus, but only one chromosome. |
Eukaryotic Cell | Found in organisms with more than one cell, they do have a nucleus. |
Cytoskeleton | The cytoplasmic network of protein filaments that plays an essential role in cell movement, shape, and division. |
Nucleus | In a eukaryotic cell, a membrane-bound organelle that contains the cell’s DNA and that has a role in processes such as growth, metabolism, and reproduction. |
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. |
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. |
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 Permeability | . |
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 | The 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. |