1.4 Flashcards
name the types of intermolecular forces that are NONCOVALENT
ionic interactions = opp charged ions
van der walls= interaction due to dipoles
name the types of van der walls
hydrogen bonding like dipole dipole interactions (polar and polar), dipole induced (can cause induction of dipole of neighboring like ch3 and make it not distrib which the methyl being less nonpolar and polar) and London dispersion(nonpolar molecules only!) which has small dipole because of fluctuations….
hydrophobic effect
the exclusion of nonpolars from polar to maximize the entropy of water molecules
atomic distances are measured as?
angstrom (A) = 10^-10 m
which has the highest bond strength? covalent or non covalent?
covalent
despite being weak, why are London dispersion important?
interactions for making nonpolar substances liquid temp like benzene
electroneg
atom attracts a shared pair of electrons toward itself
electrostatic polarization
electro neg btwn atoms in coval bond but are not evenly distr which causes dipoles to form (charge separation)
hydrogen bonding
- basically van der walls
- hydrogen bonded to oxygen or nitrogenwhich causes greater the direction and dipole
- nitrogen is electropos
- oxygen is electroneg
- makes water a liq at room temp?
why is water highly polar?
it can be a proton donor or acceptor
van der walls radius of h20?
1.4 angstrom
radius is btwn the center and the envelope
van der walls of H
1.2 angstrom
how many degrees is water shape?
104 degrees
van der walls envelope
outer boundary of the cloud of electrons
concave vs convex
degree < 180 is convex
deg > 180 is concave
what happens with ice bonding?
it is structurally ordered with hydrogen bonds, static (doesn’t move) but it can form 4 bonds with other water molecules because it has tetrahedra shape
densities of ice and water
ice = 0.92 g/ml water= 1.00 g/ml
liq water
loose h bonds that fluctuates and tumbles on a picometer
bonds to mers(3,4,5 water molecules) but it is not a permanent bonding. they are transient because they often break
bonds are held more TIGHTLY THAN ICE
H2O is aka
universal solvent
y can water dissolve polar substances
b/c its dipole character can weaken attractive opp charges molec like salt water
aggregate
can still go in water but cannot easily dissolve in it like oil and lipids
- nonpolar rather stick to each other to minimize contact with water, SA, and loses less entropy
- NONPOLAR MOLEC form non homogenous droplets
hydration
water molec neutralizes the charge of an ion
amphillic molecules
homogenous but do not dissolve but disappear into solution
hide their hydrophobic but expose their hydrophilic
amphi
both
phillia
attraction
nam 4 aggreg of artif synthetic membrane systems
micelles
bicelles
liposomes
nanodisks
diff btwn micelles and others
only one with monolayer
describe micelles
sphere shape, detergent sds is in it, single tailed
can have a central cavity filled with water depending on concen of detergents
heads are polar so it protecs nonpol and is on outside of sphere
biceles
disk like shape b/c there is too much crowding, two dif length of tails, tails form lipid bilayer NOT B/C OF TAILS
liposome
3d structure with a single bilayer with central aqueous cavity
- really a disrupted bicelle
- delivery of hydrophilic drugs and nutrients in the central cavity b/c it doesn’t readily diffuse
nanodisks
has msp (membrane scaffold amphiathic proteins) that protect the outer tails -best for stabilizing/ folding proteins
nanodisks vs bicelles
bicelles have a poor 3d structure that is heterogenous
what do the integral membrane proteins do?
they penetrate the lipid bilayer and laterally swim across
-form alpha or beta with hydrophobic surfaces
-hydrophobic, non transmembrane,non soluble and precipitates out
lateral vs transverse
lateral is fast and moves within same leaflet
transverse (rare) is slower and moves between the the inner and outer leaflet
inner vs outer leaflet
inner is the leaflet on the cytoplasmic side whereas the outer leaflet is on the outside of the cell
diff btwn the motion of heads and tails
the tails can move around and are more fluid but the heads are more restricted and cannot move bc unfavorable
what is the fluidity of the lipid bilayer dependent on?
temp and lipid composition
transition temp
phase transition in vitro from a liquid sol to a liquid crystal
temp above tm
too fluid and mobile
cholesterol decreases the fluidity by interrupting space of lipid tails
temp below tm
gel like solid of ordered array
increases the bilayer fluidity by interrupting the close packing of the tails
cholesterol
fluidity buffer to respond to temp to help the tm
peripheral membrane proteins (pmp)
water soluble and deals with lipid heads
transmembrane and can go from inner to outer leaflet vice versa
beta barrel transmembrane
- forms closed hollow tunnel
- ex:omPf
- passage of nutrients, salts, and water
alpha helical transmembrane
- transverse through bilayer once or more
- responsible for signal transduction and energy
polar heads are aka
non transmembrane
pmp are responsible for
signaling and shape of mosaic fluid model
allows attachment of spectrin actin and ankyrin to the inner leaflet for membrane skeleton
types found on inner leaflet
sphingomyelin and phosphotidycholine
types found on outer leaflet
phosphotidyethanolamino and phosphatidyserine
3 types of transverse diff
- flippase (move from outer to inner leaflet with ATP)
- floppase (inner to outer leaflet with ATP)
- scramblase (bidirectional of leaflets without atp but to meach for equilib)
