Membrane Structure and Function Flashcards
Contents of the phospholipid bilayer
Hydrophilic head, hydrophobic tails, hydrophobic tails, hydrophilic head
Fluid mosaic model
the membrane is a mosaic of proteins molecules bobbing an a fluid bilayer of phospholipids
Unsaturated hydrocarbon tails
tails that are kinked and prevent packing, enhancing membrane fluidity
Viscous hydrocarbon tails
unsaturated tiles pack together, increasing membrane viscosity
Integral proteins
penetrate the hydrophobic interior of the lipid bilayer
Peripheral proteins
appendages loosely bound to the surface of the membrane
Functions of membrane proteins
transport, enzyme activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytoskeleton and the ECM
Permeability of the lipid bilayer
nonpolar molecules can cross easily as they are hydrophobic
Transport proteins
Channel proteins that certain molecules or ions can use its hydrophilic tunnel to pass through the membrane
Carrier proteins
proteins that hold and change shape that shuttles things across the membrane
Diffusion
the spontaneous movement of particles of any substance so that they spread out into available space until dynamic equilibrium is reached
Concentration gradient
the region along which the density increases or decreases; potential energy and drives diffusion
Passive transport
transportation of substances that does not require the cell to expend energy
Osmosis
the passive transport of water; diffusion of water across a selectively permeable membrane
Facilitated Diffusion
passive transport aided by proteins