Cytoskeleton and Cell Junctions

1. 1Which of the following molecules can be exchanged between cells via gap junctions?

   1. ANa+
   2. BGlucose
   3. CHistidine
   4. DGuanine
   5. EInsulin
   6. FGlycogen
   7. GtRNA
   8. HVitamins
2. 2Which channel-forming proteins are predominant in vertebrates' gap junctions?

   1. AConnexins
   2. BInnexin
3. 3Molecules of which size are able to pass from cell to cell through gap junctions?

   1. A50 Da
   2. B100 Da
   3. C1000 Da
   4. D5000 Da
   5. E10,000 Da
   6. F20,000 Da
4. 4What is the name of the complex depicted below?

   

   1. Aconnexons
5. 5What are the subunits of a gap-junction called?

   

   1. Aconnexins
6. 6What are the terms used to describe these types of intercellular channels?

   

   1. Ahomotypic
   2. Bheterotypic
   3. Cheterotypic
7. 7What is this type of channel (only opens into one cell) called?

   

   1. Ahemichannel
8. 8What is the result of using different combinations of connexins to form gap junctions?

   1. AAllowing different types of molecules to go through (different permeability)
   2. BNo particular reasons
   3. CTo prevent backflow of molecules from the destination cell to the origin cell
   4. DA special combination of connexins allows signalling proteins to pass through
9. 9In response to a sharp decrease in intracellular Ca2+, the gap junctions to neighbouring cells will be quickly opened, allowing Ca homeostasis to be regained.

   1. AVerdadero
   2. BFalso
10. 10In response to an increase in incoming light intensity, dopamine _____ gap-junction permeability between retinal neurons.

    1. Adecreases
    2. Bincreases

11. 11Gap junctions have the same makeup throughout the body's different tissues.

    1. AVerdadero
    2. BFalso
12. 12Which of the following will most likely influence the physical properties of a tissue?

    1. AThe size of tight junctions between cells
    2. BThe amount of collagen fibre in the ECM
    3. CThe number of cells in the tissue
    4. DThe elasticity of the individual cells
13. 13The basal lamina is also known as the [blank_start]basement membrane[blank_end].

    1. Abasement membrane
14. 14What is true about the synthesis of the basal lamina?

    1. AThe only type of cells responsible for synthesizing the lamina is epithelial cells.
    2. BThe only type of cells responsible for synthesizing the lamina is stroma cells.
    3. CThe basal lamina is synthesized in the local ECM.
    4. DOne set of basal lamina is contributed by epithelial cells while stroma cells contribute the other.
15. 15Some epithelia do not have an underlining basal lamina.

    1. AVerdadero
    2. BFalso
16. 16Two main classes of basal lamina:
    - [blank_start]Fibrous proteins[blank_end]: [blank_start]glycoproteins[blank_end] with short oligosaccharide side chains.
    - [blank_start]Proteoglycans[blank_end]: core protein covalently linked to [blank_start]glycosaminoglycans[blank_end].

    1. AFibrous proteins
    2. BProteoglycans
    3. CProteoglycans
    4. DFibrous proteins
    5. Eglycoproteins
    6. Flipoproteins
    7. Gglycosaminoglycans
    8. Hphospholipids
17. 17Gap junctions in plants are called [blank_start]plasmodesmata[blank_end].

    1. Aplasmodesmata
18. 18Sort the following into the proper class of basal lamina:
    - Aggrecan: [blank_start]__[blank_end]
    - Decorin: [blank_start]__[blank_end]
    - Fibrillar collagen: [blank_start]__[blank_end]
    - Fibronectin: [blank_start]___[blank_end]
    - Hyaluronan: [blank_start]___[blank_end]
    - Nidogen: [blank_start]___[blank_end]
    - Type IV collagen: [blank_start]___[blank_end]
    - Perlecan: [blank_start]___[blank_end]
    - Laminin: [blank_start]___[blank_end]

    1. AProteoglycans
    2. BFibrous proteins
    3. CProteoglycans
    4. DFibrous proteins
    5. EFibrous proteins
    6. FProteoglycans
    7. GFibrous proteins
    8. HProteoglycans
    9. IProteoglycans
    10. JFibrous proteins
    11. KFibrous proteins
    12. LProteoglycans
    13. MFibrous proteins
    14. NProteoglycans
    15. OProteoglycans
    16. PFibrous proteins
    17. QFibrous proteins
    18. RProteoglycans
19. 19The polypeptide chains of laminin-1 are held together by _____?

    1. AHydrogen bonds
    2. BDisulfide bridges
    3. Cvan der Waals interactions
    4. DIonic bonds
20. 20Which of the following does NOT directly bind proteins of its own kind?

    1. ANidogen
    2. BType IV collagen
    3. CPerlecan
    4. DLaminin
21. 21The hereditary kidney disorder caused by a type IV collagen mutant that leads to an irregularly thickened and dysfunctional glomerulus filter is known as the [blank_start]Alport syndrome[blank_end].

    1. AAlport syndrome
22. 22The thick basal lamina in the kidney glomerulus prevents the passage of macromolecules __________.

    1. Afrom the blood into the urine
    2. Bfrom the urine into the blood
23. 23Which cells are NOT allowed to pass through the basal lamina?

    1. AFibroblasts
    2. BMacrophages
    3. CLymphocytes
    4. DCancer cells
24. 24In both inside-out and outside-in activation of the cell - ECM attachment, the signal comes from the extracellular side of the plasma membrane.

    1. AVerdadero
    2. BFalso
25. 25The [blank_start]Velcro[blank_end] principle is a term used to describe the increased adhesion strength between the cell and the ECM due to the increasing number of receptor-ligand interactions but not the binding affinity.

    1. AVelcro
26. 26Integrins are rigid rods that span the membrane and link binding sites outside the cell to those inside the cell.

    1. AVerdadero
    2. BFalso
27. 27Cell growth is dependent on an attachment to a substrate. Cell not attached to an ECM would eventually undergo apoptosis. What is this phenomenon called?
    [blank_start]anchorage dependence[blank_end]

    1. Aanchorage dependence
28. 28Which of the following components of the ECM is NOT a trimer?

    1. AType IV collagen
    2. BLaminin-1
    3. CFibronectin
29. 29Which of the following proteins of the ECM is NOT heteromeric?

    1. AType IV collagen
    2. BFibronectin
    3. CLaminin-1
30. 30FAK stands for [blank_start]focal adhesion kinase[blank_end].

    1. Afocal adhesion kinase
31. 31What does the Talin - FAK - Fyn signalling pathway do?

    1. ADisassemble focal adhesions
    2. BStrengthen existing focal adhesions
    3. CAssemble new focal adhesions
32. 32Which is NOT an anchoring junction?

    1. Adesmosome
    2. Bhemidesmosome
    3. Cadherens junction
    4. Dactin-linked cell-matrix adhesion
    5. EDelta-Notch
33. 331) [blank_start]Anchoring[blank_end] junctions: includes both cell-cell adhesions and
    cell-matrix adhesions, transmit stresses and are tethered to
    cytoskeletal filaments inside the cell.
    2) [blank_start]Occluding[blank_end] junctions: seal the gap between cells in epithelia
    so as to make the cell sheet into an impermeable (or
    selectively permeable barrier).
    3) [blank_start]Channel-forming[blank_end] junctions: create passageways linking the
    cytoplasm of adjacent cells.
    4) [blank_start]Signal-relaying[blank_end] junctions: allow signals to be relayed from
    cell to cell across their plasma membranes at sites of cell-cell
    contact.

    1. AAnchoring
    2. BOccluding
    3. CChannel-forming
    4. DSignal-relaying
34. 34Which type of cytoskeletal filament is attached to desmosomes and hemidesmosomes?

    1. ABoth actin and intermediate filaments
    2. BActin
    3. CIntermediate filaments
    4. DMicrotubule
35. 35Fill in the blanks in the following diagram:

    

    1. Aoccluding
    2. Btight junction
    3. Ccell-cell anchoring
    4. Dchannel-forming
    5. Ecell-matrix anchoring
    6. Fadherens junction
    7. Gdesmosome
    8. Hgap junction
    9. Ihemidesmosome
    10. Jactin-linked cell-matrix adhesion
36. 36Which inorganic ion is essential for cadherin to properly function?

    1. ACl-
    2. BMg2+
    3. CCa2+
    4. DK+
37. 37Cadherins mediate [blank_start]homophilic[blank_end] adhesion.

    1. Ahomophilic
    2. Bheterophilic
    3. Chomotypic
    4. Dheterotypic
38. 38Cadherins exist in many different isoforms to allow the mediation of specific homophilic attachments in different cell types.

    1. AVerdadero
    2. BFalso
39. 39Cadherin creates a strong attachment between two cells.

    1. AVerdadero
    2. BFalso
40. 40Cadherins mediate highly [blank_start]selective recognition[blank_end], allowing cells of the same type to stick together, excluding other types. The homophilic binding of cadherins controls the processes of [blank_start]tissue segregation[blank_end].

    1. Aselective recognition
    2. Btissue segregation
41. 41In a mixture of cells expressing high/low level of E-cadherin, the cells with a high level of E-cadherin expression will be positioned _______ of the resulting cell mass.

    1. Aon the outer rim
    2. Bin the core
42. 42What is the prototypical example of adherens junctions in epithelial cells?
    [blank_start]adhesion belt[blank_end]

    1. Aadhesion belt
43. 43Which cell-cell anchoring junction gives epithelia mechanical strength?

    1. Adesmosome
    2. Badherens junction
44. 44Type of intermediate filaments attached to desmosomes:
    - in epithelial cells: [blank_start]keratin[blank_end]
    - in heart muscle cells: [blank_start]desmin[blank_end]

    1. Akeratin
    2. Bdesmin
45. 45Which amino acid is the most abundant in Type IV Collagen?

    1. AGlycine
    2. BArginine
    3. CProline
    4. DSerine
46. 46What are the main functions of the basal lamina?

    1. APreventing cancer cells from spreading to other tissues
    2. BActing as a selective barrier in cell movements: separating fibroblasts and epithelial cells while letting macrophages and lymphocytes pass
    3. CServes as a scaffold for regenerating cells to anchor during tissue regeneration
    4. DCreating structures such as hair/nails
47. 47Which ECM protein is not held together by disulfide bridges?

    1. AType IV collagen
    2. BLaminin
    3. CFibronectin
48. 48Fibronectin monomers cross-link to form insoluble fibrils in the ECM throughout the body.

    1. AVerdadero
    2. BFalso
49. 49Which protein gives the basal lamina its strength?

    1. AFibronectin
    2. BType IV collagen
    3. CLaminin
    4. DPerlecan
50. 50[blank_start]Laminin[blank_end] is the primary organizer of the basal lamina.

    1. ALaminin
51. 51[blank_start]ARP complexes[blank_end] nucleates branched actin filaments from the minus end.

    1. AARP complexes
52. 52[blank_start]Formins[blank_end] add actin monomers to the growing plus end.

    1. AFormins
53. 53[blank_start]Thymosin[blank_end] sequesters unpolymerized actin monomers to prevent nucleation.

    1. AThymosin
54. 54[blank_start]Profilin[blank_end] competes with thymosin for actin monomer binding and recruit them to the site of polymerization

    1. AProfilin
55. 55[blank_start]Gelsolin[blank_end] severs actin filaments in the core region.

    1. AGelsolin
56. 56[blank_start]Cofilin[blank_end] destabilizes actin filaments by binding to their core regions and twisting strongly until they snap.

    1. ACofilin
57. 57[blank_start]Tropomyosin[blank_end] binds and stabilizes actin filament core.

    1. ATropomyosin
58. 58[blank_start]y-tubulin[blank_end] nucleates microtubules from the minus end.

    1. Ay-tubulin
59. 59[blank_start]Stathmin[blank_end] sequesters tubulin dimers to prevent nucleation.

    1. AStathmin
60. 60[blank_start]Katanin[blank_end] severs microtubules by breaking longitudinal bonds.

    1. AKatanin
61. 61[blank_start]MAP2[blank_end] stabilizes the core regions of microtubules, creating highly spaced structures. [blank_start]Tau2[blank_end] carries out the same function, resulting in more tightly packed structures.

    1. AMAP2
    2. BTau
62. 62The plus end of actin filaments is protected by [blank_start]CapZ[blank_end], while the minus end is stabilized by [blank_start]ARP complexes[blank_end].

    1. ACapZ
    2. BARP complexes

Descripción

Test sobre Cytoskeleton and Cell Junctions, creado por Chau Tran el 11/02/2020.

Autor

Chau Tran

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English

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third year

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