Molecular Biology

  1. Membrane lipids are _____ molecules meaning the have both a hydrophobic and hydrophilic end
  2. the membrane ______ are embedded in the layer and perform most of the other functions of the membrane.
  3. 3 classes of membrane lipids
    1) _______(majority)
    • phospholipids
    • cholesterol
    • glycolipids
  4. Is the phospholipid tail is a kink, this kink occurs becuase of a _______ _______
    cis-double bond
  5. 4 major types of phospholipids include;
    • phosphatidyl-ethanlamine
    • phosphatidyl-serine (has negative charge/ on cytosol side of the membrane)
    • phosphatidyl-choline
    • sphingomyelin
  6. The is the only type of cell with no cholesterol in their cell compostion
    bacteria cell
  7. Some eukaryotic membrane lipids are _______ with oligosaccharides on the _________ side of the membrane
    • glycosylated
    • noncytosolic
  8. This molecule is ampipathic, contains a polar head (-OH), and contains a steroid ring structure
    cholesterol molecule
  9. Cholesterol ________ the ability of the lipid bilayer to act as a ________ barrier to small _______ substances
    • increases
    • permeability
    • water-soluble
  10. True/false(make true) : lipids can only pack into the bilayer method as in membranes.
    false: can form sperical molecules (a lipid Micelle) as well as a lipid bilayer
  11. True/False (make true): Spontaneous aggregation to spherical shape is energetically favorable
    true. Tears in layer are repaired due to spontaneous aggregation
  12. Lipids move freely in the bilayer: Name the most and least common movements of the 4 possible.
    • MOST: Lateral diffusion (within monolayer) --- from inherit kenetic energy
    • LEAST: flip-flop (rare due to lipids great fluidity)
  13. Fibroblasts can accumulate fat droplets and transform the cell into a ______
  14. True/false (make true): the lipid bilayer is symmetrical
    false. The lipid bilayer is NOT symetrical. Proteins free float and can clump anywhere in the layer where required for protein functions. Cholesterol is distributed equally
  15. The type of phospholipid faces the cytosol and has a negative charge
  16. Glycolipids face the ________ leaflet
  17. the molecules perform the specific functions of the plasma membrane
    membrane proteins
  18. MOST membrane proteins are _________________ (added oligosaccharide); termed a ________
    • glycolsylated
    • glycoprotein
  19. This part of the membrane on the ________ side is known as a glycocalyx
    • The carbohydrate layer
    • noncytosolic
  20. Which side of the membrane contains NO oligosaccharides on the molecules
    cytosol side
  21. the carbohydrate layer funtions for 2 ;
    • provides protection
    • role in cell to cell interactions
  22. _____ _____ between the apical plasma membrane (lumen of small intestine) and lateral plasma membrane restrict lateral diffusions of lateral ______
    • tight junctions
    • proteins
  23. There are _ mechanisms that restrict lateral diffusion of proteins. These restrictions function to _______________________________________________
    • 4 mechanisms
    • proteins to perform its functions
Card Set
Molecular Biology
Membrane structure