Exam II Pt. 8

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Exam II Pt. 8
2013-10-13 13:41:57
Required Reading

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  1. a.       virtually all integral membrane proteins, as well as certain membrane lipids, bear __of variable length that project outward from the plasma membrane
    chains of sugars (oligosaccharides) 
  2.                                                               i.      these carbohydrate projections form part of a layer closely applied to the outer surface of the plasma membrane called the __(or cell coat)
    1.      this extracellular material is very prominent in some types of cells, like epithelial cells that line the mammal digestive tract
  3. 2. __ is thought to mediate __ and __, provide __ to cells, serve as a __to particles moving toward the plasma membrane, and bind important __ that act on the cell surface
    • glycocalyx
    • cell-cell and cell- substratum interactions
    • mechanical protection
    • barrier 
    • regulatory factors
  4. The extracellular matrix: 1
                                                                  i.      it is an organized network of extracellular materials that is present beyond the immediate vicinity of the plasma membrane
  5. The extracellular matrix: 2
                                                                  i.      it is more than the inert packing material or a nonspecific glue that holds cells together; it provides both physical and biochemical signals that can play key regulatory roles in determining the shape and activities of the cell
  6. The extracellular matrix: 3
                                                                  i.      addition of extracellular matrix materials back to the culture dish can restore the differentiated state of the cells and their ability to manufacture their usual cell products
  7.                                                               i.      Basement membrane
    1.      continuous sheet 50 to 200 nm thick that does three things. What?
    1) surrounds nerve fibers, muscles, and fat cells and (2) underlies the basal ssurface of epithelial tissues, such as the epidermis of the skin, or the lining of the digestive and respiratory tracts, and (3) underlies the inner endothelial lining of blood vessels
  8. Basement Membrane:
    2. provide __ for the attached cells, generate __that maintain cell survival, serve as a __for __, separate adjacent tissues within an organ, and act as a __ to the passage of macromlecules
    • mechanical support
    • signals 
    • substratum 
    • cell migration
    • barrier
  9. a.       in this latter capacity, __ of the capillaries play an important role in preventing the passage of proteins out of the blood and into the tissues
                                                                                                                                          i.      more important in the kidney, where th eblood is filtered under high pressure through a __ that separates the capillaries of the glomerulus from the wall of the kidney tubules
    1.      kidney failure may result from abnormal thickening of the cell membrane
    • basement membranes
    • double-layereed basement membrane
  10. 1.      Also serve as a __ to invasion of tissues by cancer cells
    a.       Those cells that don’t lie on a __ are surrounded by less organized ECM with __
    • barrier
    • basement membrane sheet
    • treadlike fibrils
  11. Composition:

    a.       Similar macromolecules
                                                                                                                                          i.      Unlike globular proteins inside cells, those of the extracellular space are __ and secreted into extracellular space for __ into interconnected 3D network
    1.      Proteins of the ECM serve as trail markers, scaffolds, girders, wire, and glue
    2.      Alterations in the amino acid sequenceà serious disorders
    • extended, fibrous species
    • self-assembly
  12. a.       Collagen
                                                                  i.      __ that are present only in ECMs
                                                                ii.      In __kingdom
                                                              iii.      High __
                                                              iv.      Single __ protein in the human body
                                                                v.      Produced by __ (cells in connective tissues) and smooth muscle cells and epithelial cells
    • Fibrous glycoproteins
    • animal 
    • tensile strength (resistance to puling forces)
    • most abundant
    • fibroblasts
  13.                                                               i.      __types identified
    1.      Each is restricted to __, but two or more are often present together in the same ECM
    a.       Different structural and mechanical properties result from __
    • 27 
    • certain locations in body
    • different mixtures of collagens in fibers
  14.                                                               i.      Despite differences, there are two important structural features
    What is the first?
    1.      All collagen molecules are trimers consisting of three polypeptide chains, called alpha chains
  15.                                                               i.      Despite differences, there are two important structural features
    What is the second?
    1.      The alpha chains contain large amounts of proline, whose residues (and lysine’s) are hydroxylated following synthesis of the polypeptide
  16. a.       __ are important in maintaining __of the __ by forming __ between component chains
                                                                                                                                          i.      Failure to __ __ chains has serious consequences for structure and function of connective tissues (ex: scurvy [lack of vitamin C (ascorbic acid)]))
    • Hydroxylated amino acids
    • stability 
    • triple helix
    • hydrogen bonds
    • hydroxylate
    • collagen
  17. 1.      __ required as __by enzymes that add __groups to the __and __amino acids of collagen
                                                                                                                                        ii.      Along at least part of their length, the __ of a collagen molecule are wound around each other to form a __
    • Ascorbic acid
    • coenzyme 
    • hydroxyl 
    • lysine 
    • proline 
    • three polypeptide chains
    • unique, rod-like triple helix
  18. a.       A number of the collagens, including types I, II and III, are __ because they
    assemble into ridged, cable-like __, which in turn become packaged into thicker fibers that are typically large enough to be seen in LM

                                                                                                                                          i.      __ are strengthened by __ between __and __ on adjacent collagen molecules
    1.      Continues through life and may contribute to decreased elasticity of skin and increased brittleness of bones
    • fibrillar collagens
    • fibrils
    • Fibrils
    • covalent cross-links
    • lysine 
    • hydroxylysine residues
  19. a.       Provide __framework that determines many of the mechanical properties of the matrix
                                                                                                                                          i.      Properties of matrix can be correlated with the 3D organization of its collagen molecules
  20. a.       Abnormalities in fibrillar collagen formationà __
                                                                                                                                          i.      Burns or injuries to internals accumulate scar tissue, which is mostly __ (__: excessive production of collagen-containing connective tissue which occurs mostly in lungs and liver)
                                                                                                                                        ii.      Mutations in genes encoding __ can produce __, resulting in super fragile bones, thin skin and weak tendons
    • disorders
    • fibrillar collagen 
    • fibrosis
    • type I collagen
    • osteogenesis imperfect
  21.                                                                                                                                       i.      Mutations in __ alter the properties of __, causing dwarfism and skeletal deformities
                                                                                                                                        ii.      Other mutations change the __structure
    • type II
    • cartilage tissues
    • matrix
  22.                                                               i.      Not all collagens form __
    1.      one is __, whose distribution is restricted to __ (thin, supportive sheets in which type IV are organized into a network that provides __ and serves as a __for the deposition of other extracellular materials)
    a.       __contains nonhelical segments interspersed along the molecule and globular domains at each end
    • fibrils
    • type IV
    • basement membranes
    • mechanical support
    • lattice 
    • type IV collagen trimer
  23.                                                                                                                                       i.      __ make the molecule flexible, while __ends serve as sites of interaction between molecules that give the complex its __ character
                                                                                                                                        ii.      mutations in __ genes have been identified in patients with Alport syndrome (kidney disease)
    • nonhelical segments
    • globular 

    • lattice-like
    • type IV collagen