Cell Membranes Flashcards
which 3 things compose membranes?
proteins, carbs, and lipids (mostly phospholipids)
Are PL’s amphipathic?
yes because they have a phillic head and a phobic tail
which is better for you, saturated or unsaturated fatty acids?
unsatturated because double bonds cause them to bend, not solid at RT
What are peripheral membrane proteins?
proteins that sit on the surface of the membrane loosly bound through electrostatic interactions
What are integral membrane proteins?
proteins that go right through the membrane, stabelizing hydropobic interactions- some can be transmembrane- often for ion transport
What makes the ABO blood groups?
different carbs attached to the surface of RBC membranes
What is the hydrophilic head of PL mad of?
phospholipids
What is the hydrophobic tail of PL’s made of?
fatty acid
What are the 2 types of phospholipids?
glycerophospholipids and sphingo lipids that have a glycerol backbone and sphingosine backbone respectivly
What is a glycolipid?
membrane lipid found on the outer leaflet, contains carbohydrate resigues so this is a peripheral membrane protein
What is a cholesterol?
embeded in the lipid bilayer- hydrocarbon chain interacts with hydrophobic tails of membrane lipids
Which 3 lipids face the external environment in a cell membrane?
phosphatidylcholine, sphingomyelin, and glycolipids
What are integral monotropic proteins?
proteins firmly attached to one sheet of the membrane
What is the glycocalyx of of a cell?
outer carbohydrate shell where the carbs are covaelently attached (strong)
?What are the 3 functions of the glycocalyx
protection, adhesion, and identification (VIP for RBC)
What role does phosphatidl serine play in cell life?
usually PS is found on the inside of the bilayer but during apoptosis PS is shown on the outside of the cell. (flipping needs Ca++ and ATP) This is what is recognized by phagocytes
What is Niemann Pick Disease
A rare autosomal recessive disorder caused by a deficiency in sphingomyelinase which is the enzyme that breaks down sphingomyelin which is present on the outer leaflet of cells
Why is sphingomyelinase important to sphingomyelin in NP Disease?
SM cant be broken down in NP disease because sphingomyelinase doesnt work properly and so SM builds up in liver, spleen, CNS, and bone marrow cells.
S/S of NP disease?
enlarged spleen and liver because of the build up of SM in lysosomes. neuro damage and short life of 2/3 years
Cherry red spots in eyes of patients is VIP
ABO blood and transfusions what do you ave to do and why?
ABO antigens are present on the surface of RBCs and antigens to other ab may be floating around in plasma so must cross match blood before a transfusion or you can get hemolysis shock and death
Erythroblastic Fetalis
When mom is Rh- and baby is Rh+ antibdies are created in moms body against Rh. If baby #2 is Rh+ and no treatment is applied, mom’s antibodies will attack baby
what does membrane fluidity allow for?
it allows for proteins and other molecules to move laterally and rotate like with the phosphatidyl serine (PS)
3 factors that influence membrane fluidity?
temp, lipid composition, and amount of cholesterol
Transition or melting temp
temp at which the membrane crystalizes (low) above the Tm = fluid
