Biology Chpt 7-Membrane Structure and Funtion
Terms
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- having both hydrophilic and hydrophobic regions
- amphipathic (phospholipids)
- Characterisitcs of Proteins of the Membrane
- many different proteins in membranes, each region differs in protein type/concentration, dispersed along the membrane (move laterally)
- Forms an extracellular coat on the cell, gives unique cell identity, serves as bonding site for proteins
- glycocalyx
- 3 types of transport across membrane
- simple diffusion, facilitate diffusion, active transport
- substance diffuse across memberane without work by cell, high to low concentration, ex-osmosis
- simple diffusion
- IN CELL W/OUT CELL WALL solute concentration is higher outside cell-water leaves cell
- hypertonic
- IN CELL W/OUT CELL WALL solute concentrationis less outside, cell gains water and swells
- hypotonic
- nonpolar molecules diffuse with the help of transmembrane protein
- facilitate diffusion
- needs transmembrane proteins and energy to diffuse AGAINST the gradient
- active transport
- sodium potassium pump
- phosphorelation-moving potassium and sodium inside and outside of cell
- moving large molecules out of the cell otherwise not able to diffuse
- exocytosis
- bringing large particles into the cell unable to diffuse through
- endocytosis
- 3 types of endocytosis
- phagocytosis,pinocytosis, receptor mediated
- penetrate hydrophobic core of the lipid bilayer
- integral proteins
- span the membrane and extend only partway into the hydrophobic core
- transmembrane proteins
- not embedded in the lipid bilayer, appendages loosely bound to surface of membrane
- peripheral proteins
- channel proteins that pass water molecules through membrane in certain cells
- aquaporins