Epithelial Tissue (14) Flashcards
What best describes one of the cell junctions found in animal tissue?
a. Gap junctions connect to intermediate filaments in neighbour cells
b. Tight junctions anchor actin to the ECM
c. Hemidesmosomes anchor intermediate filaments to the ECM
d. Desmosomes seal the gap between epithelial cells
c. Hemidesmosomes anchor intermediate filaments to the ECM
What is a feature of tight junctions?
a. Claudin and Occludin form heterophillic linkages
b. They allow for the simple diffusion of membrane proteins
c. They are organised by scaffold proteins like E-cadherin
d. They are a meshwork of sealing strands of the transmembrane proteins claudin and occluding
d. They are a meshwork of sealing strands of the transmembrane proteins claudin and occluding
What is a feature of anchoring junctions?
a. They consist of an intracellular plaque that attaches to the cytoskeleton and transmembrane proteins that connect to other cells
b. Desmosomes and Hemidesmosomes interact with actin
c. All anchoring junctions are adherens junctions and interact with actin
d. Hemidesmosomes form a continuous belt below the tight junctions which aligns actin filaments
a. They consist of an intracellular plaque that attaches to the cytoskeleton and transmembrane proteins that connect to other cells
How can epithelial tubes form?
a. Myosin motors cause actin bundles to contract in adhesion belts and the cell narrows at the apex
b. The over expression of E-cadherin causes cells to dissociate from one another and form a tube like structure
c. Excess calcium in cells allows hemidesmosomes to release the ECM and allow tube formation
d. Kinesin carries calcium ions to the site of tube formation and the cells widen at the apex
a. Myosin motors cause actin bundles to contract in adhesion belts and the cell narrows at the apex
Which kind of junction involves classical cadherins?
a. Tight junction
b. Gap Junction
c. Adherens junction
d. Desmosomes
c. Adherens junction
What is not a feature of desmosomes?
a. They connect intermediate filaments between cells
b. They require interactions with A6B4 integrin
c. They distribute tensile forces
d. Connections involves desmocollin
b. They require interactions with A6B4 integrin
Which junction links cells to the basal lamina?
a. Hemidesmosome
b. Tight junction
c. Desmosome
d. Adherens junction
a. Hemidesmosome
Which is a feature of hemidesmosomes?
a. They interact with the sides of cytokeratin filaments
b. They involve the adapter proteins plakoglobin and plakophillin
c. They attach to the ECM via integrins
d. They allow water soluble molecules to pass between cells
c. They attach to the ECM via integrins
What makes up the ECM?
a. Structural proteins such as tenascin
b. Adhesive ligands such as collagen
c. Anti-adhesive ligands such as elastin
d. Adhesive ligands such as laminin
d. Adhesive ligands such as laminin
What helps to regulate apico-basal polarity?
a. Par3/Par6/aPKC complex association with gap junctions
b. A basal crumbs complex
c. Cdc42 and Rac binding the Par3/Par6/aPKC complex at tight junctions
d. Degradation of the scribble complex
c. Cdc42 and Rac binding the Par3/Par6/aPKC complex at tight junctions
What, apart from actin polarisation, can influence epithelial cell polarity?
a. Shutdown of protein trafficiking to the apical, lateral and basal membranes
b. Signalling through gap junctions
c. Continuous, upregulated ion flow
d. Regulated secretion and absorption
d. Regulated secretion and absorption
What does driving snail or twist expression do in epithelial cells?
a. The cells lose all stem cell characteristics
b. Intestinal epithelial stem cells express mesenchymal markers
c. Intestinal epithelial stem cells lose their ability to be epithelial tissue
d. There is an absence of Lgr5 on mammary cells
b. Intestinal epithelial stem cells express mesenchymal markers
• Cytoskeletons of cells are linked in connective tissue and this forms the ECM.
F
• All anchoring junctions interact with actin.
F (actin: adherens, intermediate filaments: hemi and desmosomes)
• Homophillic adhesion and differential expression of different cadherins leads to cell sorting and tissue formation.
T
