Biochem final 2 N29-
Terms
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- what is a syndecan
- an intergral membrane proteoglycan
- what does the core protein syndecan usually have as its gag chains
-
3 heparan sulfates
2 chondroitin sulfates - what two types of domains alternate on a heparan gag chain and which one is most important biologially
- S domain and the NA domains alternate the S domain is most important biologically
- what does an integrin do
- mediates a phycical connection between the extra cellular matrix and the cytoskeleton
- what is an adhesion protein and give an example
- a membrane embedded protein that allows a continum between extracellular matrix and the interior IE Integrins
- what is a peptidoglycan
- a structural heteropolysaccharide of bacterial cell walls that prevent swelling and osmotic lysis from water
- what is the structural components of a peptidoglycan
- alternating B1-4 linked N-acetylglucosamine and N-acetlymuramic residues joined by pentaglycine cross linkes
- how do antibiotics effect bacterial cell walls
- they inactivate the transpeptidases that catalyze the formation of peptide cross links
- how do lysozymes in tears and saliva effect the wall of a bacterial cell
- they hydrolyze the B1-4 glycosidic bond
- what are two important cytoskeleton proteins
- actin and spectrin
- how are actin and spectrin connected to membrane spanning proteins
- by direct interaction or an adaptor protein ankyrin
- what are the 3 things that joining of actin and spectrin to transmembrane protiens accomplishes
-
1. stablizes the membrane against deformation
2. limits the mobility of integral membrane proteins
3. forms corrals that restrict the range of lateal diffusion of membrane lipid molecules - what are the 4 types of adhesion proteins we disscussed
-
integrin
cadherin
N-cam
selectin - what are the characteristics of an integrin adhesion protein
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alpha-beta dimeric heterotypic binding
the binding will be determined by the alpha beta domains - what are the characteristics of an cadherin adhesion protein
- homotypic Calcium dependent binding important in embrological development
- what are the characteristics of an N-cam adhesion protien
- contains immunoglobin like domains and binds hetertypically
- what are the characteristics of selectin adheshion protein
- contains a lectin domain that binds carbohydrates
- what adhesion proteins are involved in recruitment of lymphocytes to and infection or injury
- selectin and integrin
- what is rolling adhesion
- mediated by selectins for an interaction on the endothelial cell walls P-selectins with the glycoprotein ligand for P-selectins on the lymphocyte Process slows molecules down
- how do integrins work in recruitment of lymphocytes
- the integrin on the endothelial cell interacts with I-cam on the lymphocyte for a tighter adhesion of the lymphocyte (stop part)
- what does extravasation
- movement of lymphocyte into the inflamation site
- What is a membrane raft
-
a cholesterol-sphingolipid microdomain
these are resistant to detergents - what types of molecule is a lipid bilayer impermeable to
-
large uncharged polar molecules
ions
charged polar molecules - what types of molecule is a lipid bilayer permeable to
-
small uncharged polar molecules
gases -
what are two types of passive transport
(facilitated diffusion) -
channel mediated diffusion (unsaturable)
carrier mediated diffusion (saturable) - what is the purpose of having a protein transportor system
- the proteins lower the activation energy by forming non-covalent interactions with the dehydrated solute
- what is the main characteristic shared among membrane transportors
- that they are a multipass transmembrane protein
- what are 3 characteristics about the two state model for transporter function
-
1. it is energy independent
2. binding and release is concentration driven
3. two forms of the protein exist in thermal dynamic equilibrium - what is Glut 4
- a membrane transportor found in muscle and fat cells for the uptake of glucose
- how is glucose uptake regulated
-
insulin "tells" membrane vesicles to fuse with the plasma membrane
2. when glucose is low glut 4 is removed from plasma membrane to a small to large to small vesicle ready to go again - what is an aquaporin
- channel protein that is important in RBC's and nephrons to deal with abrupt changes in osmolarity
- what is an Ion selective channel
-
control permeability to ions
these are important in neurons and muscle cells - how do ion channels be selective
- the protein contains a backbone of carbonyl oxygens that is specific for certain Ions when they are dehydrated
- how does uniport and cotransport differ
-
uniport= one molecule one direction
cotransport= two molecules involved
1. symport=both same dir
2. antiport= both diff dir - how is secondary active transport driven
- driven by an primary active transports electrochemical gradient that works to power a symportor with the second molecule against its gradient
- what are some important secondary active transportors in the body
-
symport=intestinal uptake of glucose/AA
antiport=heart sodium/calcium -
what are four types of directly coupled atp-dependent pumps
(primary active transport systems) -
P-type
F-type
V-type
ABC transportors - what are three types of F-type atpases and what inhibits these
-
sodium potassium atpase
sarcoplasmic calcium pump
gastric hydrogen potassium pump
all of these are reversabley phosphoralated
inhibition by vanadate and ouabain - what is an F-type atpase
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Atp dependent H+ pumps
these are Atp synthases - what is a V-type atpase
- these are proton transporting atpases responsable for acidifing the intracellular comportments (lysosomes ect)
- what is an ABC transporter
-
contains two ATP binding domains
contains two transmembrane pumps to transport junk out of the cell - how is antibiotic resistance accomplised by pathogenic microbes
- over activity of the ABC transporters
- what is MDR1
- an ABC transporter (mulitdrug transporter) that is involved in the developement of resistance to chemotherapy in cancer
- what is CFTR
-
the transmembrane conductance regulator
an ABC family member for CL- ions
this on does NOT!!! require atp. passive - what causes cystic fibrosis
- a mutated CFTR
- what are some characteristics of the sodium potassium pump
-
P-type
maintain low intracellular Na+ and high intracellular K+
endothermic and electrogenic - how are affinities affected in the sodium potassium pump in relation to what conformation the pump is in
- depending on the side of the plamsa membrane the pump is facing, the affinities will be higher to match the ion
- what is vanadate and how does it work
- a phosphate mimic that inhibits all P-type ATPases at the dephosphoralation step (can't release K+ from protein)
- what two inhibitors specifically inhibit the sodium potassium pump
- vanadate and oubain
- why is oubain uses in heart tissue
- oubain inhites the Na+/K+ pump and therefore inhibits secondary active transport(antiport) of Ca++ out of the cell. increase in Ca++, increase contraction strength
- oubain is a close relative of what
- digitoxin or digoxin
- how does oubain differ from a cholesterol
- still has steroid backbone, but differs at C17 and has a hexose for a head group
- what are the four main roles of sterols
-
membrane structure
cardiac glycoside (digitoxin, oubain)
hormones
emulsifiers (bile acids) - name six steroid hormones
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aldosterone
testosterone
cortisol
estradiol
prednisolone
prednisone - what is the only significant way to rid the body of cholesterols
- as bile acids in the feces
- what is responsible for making fats accessible to pancreatic lipases
- bile acids by acting as emulsifing agents
- what is a common bile acid
- taurocholic acid
- what type of vitamins serve as hormone precursors
- A and D
- which vitamins are fat soluble and how are they made
-
A, D, E, K
they are made from isoprenoid compounds - T or F Vitamin D can be made endogenously
- T
- what vitamin can function as a hormone and participate in gene regulation
-
Vit A
also visual pigment in the eye
can be made from B-carotene - what does Vitamin E do
- destroys most free radicals
- why do we need vitamin K
- participates in activation of a blood clotting enzyme (prothrombin)
- what does a dolichol do
- it is an isoprnoid alcohol that carries sugars during cell wall syn and polysac addition to protiens and lipids
- what is the active hormone name for vitamin D3
- 1,25-dihydroxycholecalciferol
- what two derivities can be formed from B-carotene
-
retinoic acid (hormone signal to epithel c)
trans-retinal - T or F B-carotene and Vitamin A do not contain conjugated double bonds
-
F
they do, different from Fatty Acids - what part of vitamin E acts as the anitoxidant
- the two ring head structure is where the free radicals are captured
- what is warfarin and what does it do
-
it is a synthetic blood anticoagulant
and is used for prevention of blood clots to reduce the risk of embolism