B2.1 Membrane Transport Flashcards
What is diffusion?
-molecules move from areas of high concentration to areas of low concentration using kinetic energy
-will continue moving until a dynamic equilibrium is met
What factors influence the rate of diffusion?
-concentration gradient
-temperature
-size of molecule
-pressure differences
What is facilitated diffusion?
-like regular diffusion but uses a protein channel of carrier proteins to move solutes across the membrane without any energy
-carrier protein is slow
-they move though a channel that contains integral lipoprotein
What is special about channel proteins?
-they are ion selective and may be gated to regulate the passage of ions in response to certain stimuli
What is osmosis?
-the diffusion of water molecules from low solute concentration areas to high solute concentration area through a selectively permeable membrane
What is a hypotonic solution?
-low solute concentration, high water concentration
What is a hypertonic solution?
-high solute concentration, low water concentration
What is an isotonic solution?
-solutions with the same concentrations of both solute and water
What is saline solution?
-salted water often used to bathe organs for transplantation to maintain osmolarity
What is endocytosis?
-inward sinking of the cell membrane then pinches off to bring substances into a cell
What is active transport?
-uses membrane proteins which use ATP energy to move molecules against the concentration gradient
-protein changes shape as molecules binds on one side to release it on the other side
What is bulk trasnport?
-movement of large molecules in a membrane bound sac called a vesicle across the membrane
What is phagocytosis?
-endocytosis of particles that are solid and large
What is pinocytosis?
-when liquids are taken up by the membrane folding
What is exocytosis?
-a process where a vesicle fuses with the cell membrane to expel its bulky contents
-losses of cell membrane are replaced in this process
