Exam II Pt. 4

  1. I.                   Intercellular Junctions
    Explain the study of cells adhering to substrates in vitro.
    •                                                               i.      cell is rounded until it contacts substratum, when it sends out projections that form stable attachments
    • 1.      eventually, the cell flattens and spreads out on the substratum
  2. a.      when fibroblasts or epithelial cells spread onto bottom of a culture dish, the lower surface of the cell is not pressed uniformly against the substratum; instead, it is __
    anchored to the surface of the dish only at scattered, discrete sites, called focal adhesions
  3.                                                               i.      dynamic structures that can be rapidly disassembled if the adherent cell is stimulated to move or enter mitosis
    1.      the plasma membrane of the focal adhesion contains large clusters of __
    2.      the __domains of the __are connected by various __to __ of the __
    • integrins
    • cytoplasmic 
    • iintegrins 
    • adaptor proteins 
    • actin filaments
    • cytoskeleton
  4. a.      __ may act as type of __, collecting information about the __of the extracellular environment and transmitting that information to the __, which may lead to changes in __, __, and __                                                              i.      also play a key role in cell __, with extracellular materials
    • Focal adhesions
    • sensory structure
    • physical and chemical properties 
    • cell interior
    • cell adhesion, proliferation, or survival
    • locomotion
  5. a.      Focal adhesions are capable of creating __ or responding to such forces
                                                                  i.      these properties are expected from a structure that contains __ and __, two of the cell’s major contractile proteins
    • mechanical forces
    • actin and myosin
  6. a.      acting in opposite directions, mechanical forces applied to the surfaces of cells can be converted by __ into __in the cytoplasm
                                                                  i.      this process of __ is called __, and the __ is acting as a __by recognizing the physical properties of the environment
    • focal adhesions
    • biochemical signals
    • signal conversion
    • mechanotransduction
    • focal adhesion
    • mechanosensor
  7. 1.      the ability of cells to respond to __ is important in many cellular behaviors and can be illustrated by a study in which cells were allowed to bind to beads that had been covered with a coating of __
    a.      when the membrane-bound beads were pulled by an optical tweezer, the mechanical stimulus was __ where it generated a wave of __
    • physical forces
    • fibronectin
    • transmitted into the cell interior
    • Src kinase activation
  8. 1.      __is mediated by conformational changes in some of the adaptor proteins, such as __, that are induced by stretching
    a.      such conformational changes can expose important __ in these proteins that were previously hidden, allowing additional protein molecules ot be recruited to the __
    • mecahnotransduction 
    • talin
    • binding sites
    • adhesion complex
  9. a.      activation of the __ can transmit signals throughout the cell, including the cell nucleus, where they can promote changes in __
                                                                  i.      activation of either FAK or Src can alter __
    • protein kinases
    • gene expression
    • cell behavior
  10. a.      importance of the physical properties of a cell’s environment in influencing cellular behavior is illustrated with __ cells from adult bone marrow
                                                                  i.      when grown on __substratum, they differentiated into __
                                                                ii.      when grown on __one, they became __
                                                              iii.      even __led to __
    • mesenchymal stem
    • soft
    • nerve cells
    • stiff
    • muscle cells
    • stiffer
    • skeletal tissue
  11. a.      __ are most commonly seen in cells grown in vitro, although similar types of adhesive contacts are found in certain tissues
                                                                  i.      in the body, tightest attachment between a cell and its extracellular matrix is seen at __where the cells are anchored to the underlying __ by a specialized adhesive structure called a __
    • focal adhesions
    • basal surface of epithelial cells 
    • basement membrane
    • hemidesmosome
  12. Explain hemidesmosomes.
    1.      hemidesmosomes contain a dense plaque on the inner surface of the plasma membrane with filaments coursing outward into the cytoplasm 
  13.                                                               i.      unlike filaments of focal adhesions, which consist of actin, the filaments of the hemidesmosome are __and consist of the __
    1.      __ are classified as __filaments, which serve primarily in a __function
    • thicker 
    • protein keratin
    • keratin-containing filaments
    • intermediate 
    • supportive
  14. 1.      __filaments of the __are linked to the extracellular matrix by __, which also transmit signals from the __that affect the shape and activites of the attached epithelial cells
    • keratin 
    • hemidesmosome 
    • membrane-spanning integrins
    • ECM
  15. a.      importance of __seen in disease __, in which individuals produce antibodies that bind to proteins present in these adhesive structures
                                                                  i.      presence of __causes the lower layer of the epidermis to lose attachment to the underlying __
    1.      the leakage of fluid into the space between the epidermisà __of skin
    • hemidesmosomes 
    • bullous pemphigoid
    • autoantibodies 
    • basement membrane
    • blistering
  16. a.      Adherenes Junctions and Desmosomes: Anchoring Cells to Other Cells
                                                                  i.      cells of certain tiessues, especially epithelia and cardiac muscle, are difficult to separate from one another because they are __ by specialized __
    • held together tightly
    • calcium-dependent adhesive junctions
  17. Two types of adhesive junctions
    • 1.      adherens junctions
    • desmosomes
  18.                                                               i.      in addition to __, epithelial cells often contain other types of cell junctions along their lateral surfaces near the __
    1.      when arranged in a specific array, this assortment of surface specializations is called a __
    • adhesive junctions
    • apical lumen
    • junctional complex
  19. Adherens junctions 
    found in several sites, especially epithelia as __ that __each of the cells near its __, binding that cell to its surrounding neighbors
    2.      in this, cells are held together by __ formed between the __ of __molecules that bridge the 30-nm gap between neighboring cells
    • belts that encircle 
    • apical surface
    • calcium-dependent linkages
    • extracellular domains
    • cadherin
  20. a.      the __domain of these __is linked by __ and __ __ to a variety of cytoplasmic proteins, including __filaments of the cytoskeletom
                                                                                                                                          i.      thus, like the __of a __, the __clusters of an __ connect the external environment to the __ and provide a pathway for signals to be transmitted from the __to the __
    • cytoplasmic
    • cadherins 
    • alpha and beta catenins
    • actin 
    • integrins 
    • focal adhesion
    • cadherin 
    • adherens junctions
    • actin cytoskeleton
    • cell exterior 
    • cytoplasm
  21.                                                               i.      desmosomes
    1.      What are they?
    2.      numerous in what kind of tissues?
    3.      they contain __that link the two cells across a narrow __
    a.      __of __different from those of __= called __ and __
    • disk-shaped adhesive junctions approximately one micrometer in diameter
    • tissues under mechanical stress, like cardial and epithelial of skin and cervix
    • cadherins 

    extracellular gap

    • cadherins 
    • desmosomes
    • adherens
    • desmogleins and desmocollins
  22. Desmosomes

    1.      dense __ on the inner surface of the plasma membranes serve as sites of __for __ similar to those of __
    2.      the 3D network of ropelike __ provides __ and __ to the entire sheet of cells
    • cytoplasmic plaques
    • anchorage 
    • looping intermediate filaments
    • hemidesmosomes
    • intermediate filaments
    • structural continuity and tensile strength
  23. 1.      intermediate filaments are linked to the __ of the __ by additional proteins
    a.      importance of cadherins in __ illustrated in autoimmune disease in which antibodies are produced against one of the desmogleins
    • cytoplasmic domains of the desmosomal cadherins
    • maintaining structural integrity
  24.                                                               i.      one of the roles of integral membrane proteins is to ?
    transfer information across the plasma membrane, called transmembrane signaling, in which all cell-adhesion molecules can carry out
  25. 1.      __ and __ can transmit signals from the extracellular environment to the cytoplasm by means of __and with __
    a.      __ activate their target protein through __, whereas __ activate their protein targets through __
    integrins and cadherins

    • linkages with the cytoskeleton 
    • cytosolic regulatory molecules
    • protein kinases
    • phosphorylation
    • G proteins
    • physical interaction
  26. 1.      the engagement of an __with its __can induce a variety of responses within a cell, including changes in __, __, and __.
    a.      these changes can alter a cell's __(4)__
    • integrin 
    • ligand 
    • cytoplasmic pH or Ca2+ concentration
    • protein phosphorylation
    • gene expression
    • cell’s growth potential, migratory activity, state of differentiation, or survival
Card Set
Exam II Pt. 4