chapter 7

the boundary that separates the living cell from its surroundings

allowing some substances to cross the plasma membrane easier than others

responsible for controlling passage across cellular membranes

most abundant lipid in the plasma membrane

molecules containing hydrophobic and hydrophillic regions

hydrophobic tails of the phospholipids are sheltered inside the membrane while the hydrophillic heads are…

the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids

…are not randomly distributed in the membrane

held together by mainly weak hydrphobic interactions

… and some … can move sideways within the membranes

… may flipflop across the membrane, from oe phospholipid to the other

as temperatures cool, … switch from a fluid state to a solid state

temperatures at which a membrane solidifies depends on…

membranes rich in unsaturated fatty acids are more

membranes must be … to work properly

has different effects on the membrane fluidity of animal cells at different temperatures

at warm temps, cholesterol restrains movements of

at cool temps, cholesterol maintains fluidity by

plants use…to buffer membrane fluidity

collage of different proteins

main fabric of the membrane

determine most of the membranes functions

bound to the surface of the membrane

penetrate the hydrophobic core

intergral proteins that span the membrane

carry out several functions; transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytoskeletion and extrcellular matrix