Membranes

  1. what is the function of membrane
    sets external boundaries for cells and separates compartments
  2. what are the 7 common features of membranes
    • sheetlike, and form boundaries between cell compartments
    • contain lipids, proteins, and CHO
    • lipids forms a bilayer due to amphiphilic nature
    • function are mediated by specific proteins; pumps, channels, receptors, energy transducers, enzymes
    • membrane components associate through noncovalent interactions
    • asymmetrical
    • lipid and proteins diffuse rapidly along the plane of the membrane
  3. what is the melting temperature of saturated fatty acids (Tm)
    high
  4. what is the melting temperature of unsaturated fatty acids
    lower
  5. what does and increase in cholesterol do to the membrane
    decrease fluidity
  6. What are the common monosaccharides associated with membranes
    • glucose
    • galactose
    • fructose
    • mannose
  7. what molecules are important for cell to cell recognition
    • glycoproteins¬†
    • glycolipids
  8. How are ABO blood groups different from each other?
    Each blood group has unique antigens (polysaccharides) on the glycoproteins of the RBC membrane. The different polysaccharide chains are classified as A,B,O,AB
  9. Are CHO asymmetric and where are they found
    • asymmetric
    • outside of the cell
  10. what are the types of membrane lipids
    • sphingolipids
    • glycolipids
  11. what is sphingomyelin and where is it found
    • a membrane lipid
    • brain, blood cells, lung surfactant
  12. what are glycolipids
    identical in structure to sphingolipids except the phosphoryl choline head group is replaced with a monosaccharide
  13. what are the types of membrane proteins?
    • peripheral membrane proteins: extracellular or intracellular, can be easily removed
    • extracellular proteins: includes protein ligands specific for cell surface receptors. Includes proteins of the extracellular matrix
    • intracellular proteins: attaches to lipid anchors or integral proteins. Can be modified covalently by lipids or modified as oncoproteins
    • integral membrane proteins: span across the bilayer, has both intra and extra cellular domains. Difficult to remove unless destroying the membrane
  14. what are the classes of integral membrane proteins
    • antigens
    • receptors
    • translocators
  15. what is the structure of a transmembrane domain
    a-helical
  16. antigens
    integral membrane proteins that are recognized by antibodies
  17. receptors
    required for the specific action of hormones, transmitters, and growth factors
  18. what are two classes of membrane receptors
    • growth factor receptor tyrosine kinases (RTKs)
    • small molecule 7 transmembrane helix receptors
  19. What are RTKs
    • binds to hormones such as insulin
    • intracelluar domain: contains lots of tyrosine residues
    • extracellular domain: binds to ligand
  20. what are small molecule 7 transmembrane helix receptors
    • binds to hormone epinephrine and glucagon
    • most small molecule 7 transmembrane receptors are G-proteins
  21. function of transporters (translocators)
    • acts as a selective permeability barrier
    • transport is either active or passive
  22. what is active transport
    • transport of molecules across cell membrane using energy
    • ex: Na/K ATPase, found in all mammals
  23. what is the function of Na/K ATPase
    pumps 3 Na+ ions out and two K+ into cell expending one ATP molecule
  24. what is passive transport
    transport of molecules along electrochemical gradient
Author
tanyalequang
ID
342621
Card Set
Membranes
Description
function and components of cell membranes
Updated