| what is passive transport? | the movement of substances across the cell membrane without any input of energy by the cell |
| what is diffusion? | simplest type of passive transport. movement of molecules from an area of higher concentration to an area of lower concentration |
| what is diffusion driven by? | kinetic energy |
| what is equilibrium? | the concentration of molecules will be the same throughout the space the molecules occupy |
| what ability does a molecule depend on to diffuse across the cell membrane? | the size, type of molecule and on the chemical nature of the membrane |
| what is osmosis? | water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration |
| what is hypertonic, hypotonic and isotonic? | hypotonic less solutes more solvent
hypertonic more solutes less solvent
isotonic same |
| what are contractile vacuoles? | organelles that remove water. they collect the excess water and then contract pumping the water out of the cell |
| what is turgor pressure? | the pressure that water molecules exert against the cell wall is called turgor pressure |
| what is plasmolysis? | the cells shrink from the cell walls and turgor pressure is lost. this condition is called plasmolysis |
| what is cytolysis? | water diffuses into the cell, causing them to swell and eventually burst in a hypotonic environment. the bursting of cells is called cytolysis |
| what are carrier protiens? | the movement of molecules across the cell membrane is assisted by specific proteins in the membrane. these portions are known as carrier portions |
| what stimuli will allow gates to open in ion channels? | 1.) stretching of the cell membrane
2.) electrical signals
3.) chemicals in the cytosol or external environment |
| what is active transport? | movement of materials from an area of lower concentration to an area of higher concentration, or "up" the concentration gradient by using energy |
| what is a sodium potassium pump? | a carrier protein transports Na ions and K ions up the concentration gradient
(that carrier portion is known as sodium potassium pump) |
| what are vesicles? | external materials are enclosed by cell’s membrane during endocytosis, which folds into itself and forms a pouch. The pouch then pinches off from the cell membrane . |
| what are the types of endocytosis? | pinocytosis and phagocytosis |
| what is pinocytosis? | involves transport of solutes or fluids into cells |
| what is phagocytosis? | movement of large particles or whole cells |
| what happens in Exocytosis | During exocytosis, vesicles in cytoplasm fuse with the cell membrane, Releasing their contents into the cell’s external environment. |
| what happens in endocytosis? | Cells ingest external fluid, macromolecules, and large particles. |
