Flashcards in 2 Membrane structure Deck (23):
how much of the cell volume do membranes take up?
what two primary molecule types do cells have other than lipid attached to their membrane?
proteins and carbohydrates
what is the typical composition of protein, lipid and carbohydrate in a cell membrane
about 5-10% carbohydrate
name the types of lipids in the membrane of a cell from most to least abundant
which leaflet of the plasma membrane is more fluid and why?
-the outer leaflet
-allows lipid rafters to conentrate ligand receptor pairs at specific sites on the membrane for endocytosis
what molecule type is PGE2 and what is its function?
-induces uterine contraction
what molecule type is TXA2 and what is its function?
-induces platelet aggregation
what is the function of leukotienes? name the disease that they are strongly associated with
induce vasodilation and broncoconstriction in ASTHMA / anaphylaxis
which type of bond creates a kink in the phospholipid fatty tail and what impact does this have on the membrane? what function can it perform better?
-cis double bond
-makes the membrane more fluid. Also allows for for fusion.
What propoerty of cell membranes does HIV take advantage of when infecting its host?
Fusogenic properties of the membrane. can create a multinucleate syncytium
what property of membranes does measles take advantage of to infect its host?
what is the primary functional difference between sphingolipids and phospholipids?
sphingolipids do not have fusogenic properties. they have saturated fatty chains, making them very rigid
-Lysosomal storage disease
-mental retardation, blindness, early death
-lysosomal storage disease
-kidney failure, skin rash
Name 4 factors that effect membrane fluidity and how they effect it.
1. cis double bonds, the more you have, the more fluid the membrane
2. acyl chain length, the shorter the chain, the more fluid
3. temperature, the warmer the environment, the more fluid
4. cholesterol, at body temp, the more cholesterol the less fluid
what is the mechanism of infection of mycoplasma (walking) pneumonia?
-feeds on the cholesterol in the cilia of the lung, making the cilia more rigid and unable to clear mucus from the lungs.
what membrane components are found in large quantities in lipid rafts?
cholsterol and sphingolipids
what are 3 major functions of lipid rafts?
1. signal transduction
3. rapid reorginization of the membrane for extracellular matrix modification and motility
how many amino acids does it take to span the membrane?
what common characteristic do the amino acids spanning the membrane have?
they are hydrophobic
whats a glycoprotein?
what are 3 examples of functions of glycoproteins on the cell mebrane?
a protein with carbohydrate residues residing on it.
1. blood type antigen
2. pathogen recognition sites
3. resevoir for cytokines/growth factors
what does the toxoplasma recognize when infecting its host?
a carbohydrate on the outer surface