Key Term | Definition |
cytology | the study of cells |
fluid mosaic model | description of the composition of the plasma membranep; made up of a phospholipid bilayer with embedded proteins |
cytoplasm | all the material within the cell membrane other than the nucleus |
mitochondria | "powerhouse of the cell"; center of cellular respiration |
cristae | folds of mitochondrial membrane which contain enzymes necessary for cellular respiration |
ribosomes | non-membrane-bound organelles; function in protein synthesis |
endoplasmic reticulum (ER) | folds of cellular membranes running throughout the cytoplasm; functions in synthesis of complex compounds; a channel for movement of substances |
golgi apparatus | synthesis of complex polysaccharides and othe coplex secretions; packages substances for secretion |
lysosomes | destroys old or useless cellular structures |
cytoskeleton | system of fibers crisscrossing the inside of the cell; provides structure for the cell |
flagella | occur singly or in small groups; aid in mobility |
cilia | short, hairlike structures; aid in mobility |
plastids | storage organelles for plants, algae; NOT found in animal cells |
leucoplast | stores plant products; colorless |
chromoplast | contains pigments |
chloroplast | chromoplast that contains green pigments (chlorophyll), thylakoids, grana, filled with fluid called stroma |
vacuole | a membrane-bound sac that contains food, water, wastes, or other materials |
vesicle | a small vacuole |
nucleus | control center of the cell |
nuclear envelope | double membrane that surrounds thenucleus; contains large pores |
nucleolus | contains large areas of RNA; site of ribosome synthesis |
homeostasis | steady state of the cell; dynamic equilibrium |
optimal point | the temperature at which a cell functions best |
optimal range | where function can still take place |
range of tolerance | the temperature range in which a cell or an organism will remain alive but will not function properly |
limit of tolerance | the point outside of the optimal range where a cell dies |
isotonic solution | condition where the concentration of solutes outside the cell is the same as the concentration inside the cell |
hypotonic solution | condition where the water concentration is higher and the solute concentration is lower in the solution than inside the cell; causes cytolysis |
hypertonic solution | condition where the ratio of solutes to water is higher in the solution than inside the cell; causes plasmolysis in plants and shrinking of red blood cells |
endocytosis | the process a cell uses to transport substances in bulk across the membrane |
phagocytosis | "cellular eating" |
pinocytosis | "cellular drinking" |
exocytosis | process where vacuoles in the cytoplasm fuse with the plasma membrane and release their contents into the solution outside the cell |
passive transport | movement with concentration gradient; no energy required; no membrane protein required for transport; diffusion and osmosis |
passive mediated transport | movement with concentration gradient; no energy requiredp; membrane protein required for transport |
active transport | movement against concentration gradient; energy required; membrane protein required for transport |
cytolysis | the bursting of cells |
plasmolysis | the process where a plant cell loses too much water by osmosis and the plasma membrane pulls away from the cell wall |