cell membranes and transport Flashcards
what do phospholipids consist of
molecules containing hydrophobic and hydrophilic regions
what are the six major functions of membrane proteins
transport
enzyme activity
signal transduction
cell-cell recognition
intercellular joining
attachment to cytoskeleton and ECM
what does passive transport consist of
1) passive transport
2) facilitated diffusion
what does active transport consist of
1) primary active transport and secondary active transport
what is the final movement across membranes called
exocytosis and endocytosis
what is passive transport
diffusion of a substance across a membrane with no energy invested
what is osmosis
water diffusion from regions of low to high concentration
what is an isotonic solution
solute concentration is the same as the inside of the cell
what is a hypertonic solution
solute concentration is greater than inside the cell
what is a hypotonic solution
solute concentration is less than inside the cell
what do channel proteins do
provide corridors that allow specific molecule or ion to cross the membrane
what do carrier proteins do
undergo a subtle change in shape that translocates the solute binding site across the membrane
what does active transport require
energy in ATP
what is the most important part of active transport
sodium-potassium pump
what does uniporter do
move one molecule across a cell membrane independent of the other molecules
what does symporter do
move two molecules in the same direction through a protein channel
what does anti porter do
move two molecules in the opposite direction through a protein channel
when does co transport occur
when active transport of a solute indirectly drives transport of another solute
what does primary active transport do
the energy is derived directly from the breakdown of ATP
what does secondary transport
uses and electrochemical gradient created by the primary active transport
what is exocytosis
active process of moving materials from within the cell to the exterior of the cell
what is endocytosis
active cellular process in which substances brought into the cell
cell takes in macromolecules by forming vesicles from the PM
what is phagocytosis
cell engulfs particle in a vacuole
what is pinocytosis
extracellular fluids or small particles are ingested by the cell
what is receptor-mediated endocytosis
binding of ligands to receipts triggers vesicle formation
