BCH441 - CH 9 EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED
lipid anchored membrane proteins are switching devices
-certain proteins found covalently linked to lipids in membrane
-lipid anchors may be transient, can be reversible bount
-attachment to the lipid membrane via lipid anchor can modulate activityof protein
-4 tyypes: amide linked, thioester linked, tioester linked, glycosyl phosphatidylinositol
functions of membranes
-barrier, delimits cell from environment
-keep cell contents in, toxic molecules out
-transport and accumulation of nutrients
-energy transduction
-facilitates cell mobility
-repro
-signal trasnduction
-cell cell interactions
chemical and physical properties of membranes
-lipids self associate to form membranes becasue?
-entropy!
-biological membranes may contain as muchas 75-80% protein ro as little as 15-20%
-membranes carry out many enzyme catalyzed reactions and transport activities will be
, richer in proteins
-membranes that carry out fewer of those functions are richer in lipid
-cells adjust lipid comp of membranes to suit function needs
fluid mosaic model
-phospholipid bilayer is a fluid matric
-2d solvent
-lipids and proteins acn undergo rotational and lateral movement
-2 classes of proteins: peripheral (extrinsic), integral (intrinsic)
-also lipid anchored proteins
-CHO groups on extracellular side of membrane - glycosylation and disulfide bonds on
outside of cell - oxidizing environment
-electrostatic interactions - lipid head group binding site interacting with other proteins
"there is motion in them there bilayers"
-lipid chains can bend, tilt, rotate
-portions of the lipid chain near surface lie mostly perpindicular to plane
-lipid chain ordering decreases and motion increases towards end of chain (toward
middle of bilayer)
-lipids and proteins can migrate "diffuse" in the bilaryer
peripheral membrane proteins associate looseley with the membrane
-can dissociate with mild detergent of high ionic strenght solutions
-dance floor analogy - can spin around but hard to move across membrane with so
many other lupids
integral membrane proteins are achored firmly in the membrane
COMPLETE SOLUTIONS VERIFIED
lipid anchored membrane proteins are switching devices
-certain proteins found covalently linked to lipids in membrane
-lipid anchors may be transient, can be reversible bount
-attachment to the lipid membrane via lipid anchor can modulate activityof protein
-4 tyypes: amide linked, thioester linked, tioester linked, glycosyl phosphatidylinositol
functions of membranes
-barrier, delimits cell from environment
-keep cell contents in, toxic molecules out
-transport and accumulation of nutrients
-energy transduction
-facilitates cell mobility
-repro
-signal trasnduction
-cell cell interactions
chemical and physical properties of membranes
-lipids self associate to form membranes becasue?
-entropy!
-biological membranes may contain as muchas 75-80% protein ro as little as 15-20%
-membranes carry out many enzyme catalyzed reactions and transport activities will be
, richer in proteins
-membranes that carry out fewer of those functions are richer in lipid
-cells adjust lipid comp of membranes to suit function needs
fluid mosaic model
-phospholipid bilayer is a fluid matric
-2d solvent
-lipids and proteins acn undergo rotational and lateral movement
-2 classes of proteins: peripheral (extrinsic), integral (intrinsic)
-also lipid anchored proteins
-CHO groups on extracellular side of membrane - glycosylation and disulfide bonds on
outside of cell - oxidizing environment
-electrostatic interactions - lipid head group binding site interacting with other proteins
"there is motion in them there bilayers"
-lipid chains can bend, tilt, rotate
-portions of the lipid chain near surface lie mostly perpindicular to plane
-lipid chain ordering decreases and motion increases towards end of chain (toward
middle of bilayer)
-lipids and proteins can migrate "diffuse" in the bilaryer
peripheral membrane proteins associate looseley with the membrane
-can dissociate with mild detergent of high ionic strenght solutions
-dance floor analogy - can spin around but hard to move across membrane with so
many other lupids
integral membrane proteins are achored firmly in the membrane
