Biomembranes Flashcards
average amount of body water
65%
how is body weight different in obese people
lower percentage of body weight as water
ICF is how much of body weight
40%
ECF is how much of total body weight
20%
what are the 2 components of ECF
interstitial fluid
plasma
What is the main cation of ECF
Na+
what are the main anions of ECF
Cl- and HCO3-
what is the main cation of ICF
K+
what are the main anions of ICF
proteins and phosphate
where are integral membrane proteins
imbedded in the membrane
where are peripheral membrane proteins
inner or outer face of membrane
where are carbohydatres located on membrane
extracellular face and luminal side of endoplasmic reticulum/golgi membranes
what is the amount of protein and lipid in most membranes
50/50
how much protein is the innermitocondrial membrane
70%
how much protein is the myelin
20%
structure o fmembrane lipids
polar head and hydrophoic tail
what are the most abundant membrane lipids
glycerophospholipids
phosphatidylinositol
a phosphoglyceride form which important signaling molecules are derived
plasmalogens
phosphoglycerides with ether linkage
plasmalogens are important where
myelin sheath
where are plasmmalogens synthesized
peroxisomes
what is Zellwger syndrome caused by
failure to produce functioanl peroxisomes
what are the symptoms of Zellweger syndrome
hypotonic
high forehead
flat broad nasal bridge
micrognathia
micrognathia
underdevelopment of jaw
what are sphingolipids dervied from
long chain alcohol sphingosine
what does sphingomyelin codntain
sphingosine, fatty acyl group, phosphorylcholine
phase transition
bilayer chaing from fluid to rigid form at specific temp
phase transition temperature is lowered by the presence of what
short chain fatty acyl groups
cis-double bonds
cholesterol
function of cholesterol
can both incrase and decrease fluidity
at body temp what does cholesterol do
limits fluidity
at reduced temp what does cholesterol do
maintain fluidity
integral membrane proteins
contain 1 or more hydrophobic regions that pass through the lipid bilayer
what do integral membrane proteins usually form
alpha helix
example of integraph membrane protein
glycophorin
how do peripheral membrane proteins attach
electrostatic interactions
covalently attach
attach to phosphatidylinositol
interact with intergral membrane proteins
what are the 3 classes of transport protein that allow passage of material into and out of cell
channela nd pore
facilitated trasnproted
active trasnport
pores
openings that are non-specific
channels
specific for particular ions
gap junctions all for waht
movement of small molecules between 2 adjacent cells
connexon
penetrate lipid bilayer
how many subunits are there is the nicotinic acetylcholine receptor
5 - 2 alpha, 1 beta, gamma, and delta
how is the nicotinic acetylcholine receptor specific
size of opening and presence of neg charged amino acid side chains in the opening
how do alpha neurotoxins cause paralysis
blocking the actino of nicotinic acetylcholine receptor
what does facilitated diffusion show
saturation kinetics
what is the biggest user of ATP when you are at rest
Na+/K+ATPase
what triggers the conformation change in Na+/K+ATPase
phosphorylatuion
what does digitalis do
inhibits Na+?K+ATPase
how does digitalis affect the heart
incrases intensty of heart muscle contraction, but decreases rate
what drives transport in secondary active transport
energy of electrocehmical ion gradents
symport
2 things going in or out
antiport
1 thing going in ,1 thing going out
