Exam 3: RR (1)

  1. Animal tissue has an __ within the cytoplasm containing long channels bounded by __radiating through the cytoplasm to form an __; and stacks of flattened membrane-bound sacs, called __. These membranous compartments form separate __, each of which contains a particular __ and is specialized for particular types of activities. The cytoplasm of a cell, therefore, is divided into __ for analogous reasons. These membranes are the __.
    • extensive membrane network
    • membranes 
    • interconnected network of canals
    • cisternae
    • organelles
    • complement of proteins
    • specialized membranous compartments
    • Endomembrane system
  2. a.      organelles of the __ are part of a dynamic, integrated network in which materials go from one part of the cell to another __between organelles in small, membrane-bound __ that budfrom the __
    • Endomembrane system
    • shuttled 
    • transport vesicles
    • donor membrane compartment
  3. How do transport vesicles move? 
    Once they reach their destination, what happens? 
    What occurs repeatedly?
    • transport vesicles move in a directed manner, pulled by motor proteins that operate on tracks formed by the cytoskeleton
    •                                                               i.      the vesicles fuse with the membrane of the acceptor compartment, which receives the vesicle’s cargo as wel as its membranous wrapper

    budding and fusion
  4. a.      __: can be seen in which proteins are synthesized in the __, modified in the __, and transported (also called a __ since many of the proteins made in the __are destined to be __)
    • biosynthetic pathway
    • ER
    • Golgi
    • secretory pathway
    • ER 
    • secreted from the cell
  5. two types of secretory activities
    • constitutive
    • regulated
  6. Constitutive secretion
    • 1.      constitutive secretion: materials transported in secretory vesicles from their sites of synthesis and discharged into extracellular space in a continual manner
    • a.      this helps form the ECM and the plasma membrane
  7. Regulated secretion
    • 1.      regulated secretion: materials stored as membrane-bound packages and discharged only in response to an appropriate stimulus (ex: nerve cells)
    • a.      in some of these cells, materials to be secreted are stored in large, densely packed, membrane-bound secretory granules
  8.                                                               i.      proteins, lipids, and complex polysaccharides are transported through the cell along __
    1.      integral and soluble proteins reside within the various __, while __ are discharged
    2.      by following the __, materials move from the outer surface of the cell to compartments, such as endosomes and lysosomes, located within the cytoplasm
    • the secretory pathway
    • endomembrane compartments
    • soluble are discharged
    • endocytic pathway
  9.                                                               i.      __ are required to ensure that materials are accurately delivered to the appropriate sites; material will be targeted  to places
    1.      different organelles aso contain different __--> membrane proteins must be __ to particular organelles
    • traffic patterns
    • integral membrane proteinsà
    • targeted
  10. 1.      these various types of cargo are routed to their appropriate cellular destinations by __ that are encoded in either the __ of the proteins or __
    a.      __ are recognized by specific receptors that reside in the __ or __ of __, ensuring that the protein is transported to the right place
    b.      the machinery responsible consists of __ that are recruited to specific membrane surfaces
    • “addresses” or sorting signals
    • amino acid sequence
    • attached oligosaccharides
    • sorting signals
    • membranes or surface coats of budding vesicles
    • soluble proteins
  11. 1.      traffic patterns have been __, addresses and receptors identified
    Knowing the structure but not the function leads to __
    • mapped
    • new techniques
  12. Autoradiography:
    -acinar cells
    extensive endomembrane system that function in synthesis and secretion of digestive enzymes, are shipped through ducts of the s. intestine where they break down food
  13. Autoradiography:

                                                                  i.      to follow the steps of a single cycle from start to finish, __ and __ utilized autoradiography
                                                                ii.      provides a means to visualize __ by allowing an investigator to determine the location of __ materials within a cell
    • George Palade and James Jamieson
    • biochemical processes
    • radioactively labeled
  14. Autoradiography technique
                                                                  i.      technique: tissue sections with radioactive isotopes are covered with photographic emulsion, which is exposed by radiation emanationg from radioisotopes within the tissue; sites containing these are seen under the microscope
  15. Autoradiography:

    1.      to determine sites where __ proteins are made, Palade and Jamieson incubated __tissue in solution containing __ for a brief period of time at which time labeled __ were taken up by the living cells and incorporated into the __as they were being synthesized on ribosomes
    • secretory
    • pancreatic 
    • radioactive amino acids
    • amino acids
    • digestive enzymes
  16. a.      tissues fixed and locations of proteins that were made during the incubation with labeled amino acids were determined __
    2.      the __was discovered to be the site of synthesisi of secretory proteins through this
    • autoradiographically
    • ER
  17.                                                               i.      to determine the intracellular path followed by secretory proteins from their site of synthesis to their site of discharge, they incubated tissue in radioactive amino acids, washed the tissue free of excess isotope and transferred the tissue to a medium containing only __= __
    unlabeled amino acids

  18. Explain pulse and chase and their relationship.
    • 1.      pulse= brief incubation with radioactivity during which labeled amino acids are incorportated into proteions
    • 2.      chase= period when the tissue is exposed to the unlabeled medium, a period during which additional proteins are synthesized using nonradioactive amino acids
    • 3.      the longer the chase, the farther the radioactive proteins made during the pulse will have traveled
  19.                                                               i.      with this approach, one can follow newly made molecules
                                                                ii.      results of these experiments first defined the __ and tied a number of separate __ into an __
    • biosyntheitic pathway
    • membranous compartments
    • integrated functional unit
  20. a.      Green Fluorescent Protein
                                                                  i.      allows following __of specific proteins with their own eyes by using __, which emits a green fluorescent light
    1.      DNA encoding __ is fused to DNA encoding the protein to be studied, and the resulting __ is introduced into cells that can be observed under the microscope
    • dynamic movements 
    • GFP
    • GFP
    • chimeric DNA
  21. a.      once in, the __expresses a __ with __at the end, which doesn’t alter movement or functioning of that protein
                                                                ii.      ex: __ has __ fused to GFP, causing production of the viral proteins, which are carried through the __, made in thee __, trafficted through the __ and transported to the plasma membrane
    1.      mutants that function normally at a reduced temperature, but not at an evelated temperature are __
    • chimeric DNA 
    • chimeric protein
    • GFP 
    • VSV (vesicular stomatitis virus)
    • VSVg gene
    • biosynthetic pathway
    • ER
    • Golgi complex
    • temperature-sensitive mutants
  22.                                                               i.      electron microscopy, autoradiography, and the use of GFP provide information on the structure and function of cellular organielles, but don’t provide insight into __
                                                                ii.      techniques to break up (__) cells and isolate particular types of organelles were made by __ and __
    • molecular composition
    • homogenize
    • Albert Claude and Christian De Duve
  23.                                                               i.      when a cell is ruptured by __, the cytoplasmic membranes become fragmented and the fractured edges of the membrane fragments fuse to form __ less than 100 nm in diameter
    1.      vesicles derived from different organelles have different properties, which allow them to be separated from another, called subcellular fractionation
    • homogenization
    • spherical vesicles
  24.                                                               i.      membranous vesicles derived from the __ form a __collection of similar sized vesicles called __
    1.      a __ is done and further fractionated into smooth and rough membrane fractions by gradient techniques
    • endomembrane system
    • heterogeneous 
    • microsomes
    • microsomal fraction
  25. 1.      once isolated, the __ of various fractions can be determined
    a.      once a particular organelle has been isolated, the proteins can be extracted, separated, and identified by __
    • biochemical composition
    • mass spectrometry
  26.                                                               i.      __: isolated parts of a cell that provided a wealth of information about biological processes that were impossible to study within the complex environment of intact cells
                                                                ii.      scientists found that they could strip a __ preparation of its attached particles, and the isolated particles were capable of synthesizing proteins when provided with required ingredients from the cytosol
    • cell-free systems
    • rough microsomal
  27. 1.      under these conditions, the newly synthesized proteins were simply __by the __ into the aqueous fluid of the test tube
    when the same experiment was carried out using intact __, the newly synthesized proteins were no longer released into the __medium but were trapped within the __ of the __
    • released 
    • ribosomes
    • rough microsomes
    • incubation 
    • lumen
    • membranous vesicles
  28. Conclusion: __ was not required for the incorporation of amino acids into proteins but for sequestering newly synthesized secretory proteins within the __
    microsomal membrane

    ER cisternal space
  29.                                                               i.      __ used to study __, such as with __(vesicles whose surface consists of an artificial bilayer created in the lab from purified phospholipids)
    • cell-free systems
    • membrane trafficking
    • liposomes
  30. 1.      buds and vesicles were produced after prep of __was incubated with__ that normally comprise coats on the __ of __ within the cell
    a.      without the added __, __ could not occur
    • liposomes 
    •  purified proteins
    • cytosolic surface
    • transport vesicles
    • coat proteins
    • vesicle budding
  31. a.      using this strategy in which cellular processes are reconstituted __ from purified components, researchers have been able to study the proteins that __, the proteins responsible for __, and the proteins that __
    • in vitro
    • bind to the membrane to initiate vesicle formation
    • cargo selection
    • sever the vesicles from the donor membrane
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Exam 3: RR (1)