Topic 2.6 - Membrane Transport 𖦹⋆｡°✩ Flashcards
what do selectively permeable membranes allow for
they allow for the formation of concentration gradients
what is a concentration gradient
when a solute is more concentrated in one area than another. a membrane separates 2 different concentrations of molecules
what is passive transport
the net movement of molecules from high to low concentration without metabolic energy (like ATP) needed
what does passive transport play a primary role in
plays a primary role in the import of materials and the export of wastes
what is diffusion
the movement of molecules from high to low concentration
༻ small nonpolar molecules pass freely (N2, O2, CO2)
what is facilitated diffusion
the movement of molecules from high to low concentration through transport proteins
what does facilitated diffusion allow for
allows for hydrophilic molecules and ions to pass through membranes
what does active transport require
the direct input of energy (ATP) to move molecules from regions of low concentrations to regions of high concentrations
what does endocytosis require
requires energy to move large molecules into the cell
what happens in endocytosis
in endocytosis, the cell uses energy to take in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane
what is phagocytosis
cell takes in large particles
what is pinocytosis
cell takes in extracellular fluid containing dissolved substances
what is receptor-mediated endocytosis
receptor proteins on the cell membrane are used to capture specific target molecules
what is required for exocytosis
exocytosis requires energy to move large molecules out of the cell
what happens in exocytosis
internal vesicles use energy to fuse with the plasma membrane and secrete large macromolecules out of the cell
༻ proteins (ex. signalling proteins)
༻ hormones
༻ waste
