Chapter 7 Flashcards
what molecules make up the plasma membrane
phospholipids, glycolipids, sterols, membrane proteins
where are hydrophobic amino acids usually located?
interior of protein and interior of membrane
what are transport proteins
allow things to come through lipid bilayer
where do hydrophilic amino acids tend to be located?
exterior of the protein
What is an erythrocyte
No nucleus or other organelles
red blood cell
Lipid rafts
cluster of lipids and proteins in the plasma membrane
Functions of the membrane
Defines the boundaries Loci for specific functions Transport proteins Receptors Cell-to-cell communication
Fluid mosaic model
membrane has a mosaic of proteins embedded in or attached to it
Three major classes of membrane lipids
Phospholipids, glycolipids, sterols
Phosphoglyceride
type of phospholipid
Glycerol based
common in plants and bacteria
Sphingolipid
type of phospholipid
sphingosine based
common in animal
General functions of membrane proteins
transporters, receptors, and adhesion
three classes of membrane proteins
integral, peripheral, lipid-anchored
Three types of movement of the membrane
rotation, lateral diffusion, transverse diffusion
lateral diffusion
lipids trading places in the plane of the membrane
transverse diffusion
lipids passing through membrane interior to the other side (rare)
Tm
transition temperature of lipids from a gel to a fluid
affect of chain length on Tm
longer chains have higher Tm
high Tm means
less fluid
Saturated fatty acids affect on Tm
higher Tm
Sterols affect on membrane at high temperatures
decrease fluidity
Sterols affect on membrane at low temperatures
increase fluidity (because phospholipids can’t get as close together)
Monotopic membrane proteins
embedded in single layer of lipid membrane (doesn’t span the whole thing)
Bitopic membrane proteins
single pass through membrane
Multitopic membrane proteins
multipass
Peripheral membrane proteins associate with…
just lipids, just integral membrane proteins, or both
Evidence for the mobility of membrane proteins
freeze-fracture images and mouse and human cell fusion
Glycoproteins and glycolipids form…
Glycocalyx- carbohydrate coating on exoplasmic leaflet
Functions of glycoproteins
defense, adhesion, cellular uptake, and embryonic development
