MST2 L14-25 Questions 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 occludin
d. They are a meshwork of sealing strands of the transmembrane proteins claudin and occludin
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
• Classical cadherins in adherens junctions link to intermediate filaments via catenins.
F (actin)
• Desmosomes interact with the side of cytokeratin filaments and hemidesmosomes interact with the ends of cytokeratin filaments.
T
• A hemidesmosome is a specialised ECM that underlies all epithelia.
F (BL)
• Neural crest cells are more mesenchymal like than neural tube cells.
T
What makes up skin?
a. Keratinocytes are found mostly in the dermis
b. Hair follicles grow from the epidermis
c. Pericytes are unique to the epidermis
d. Epidermis regenerates due to basal keratinocytes
d. Epidermis regenerates due to basal keratinocytes
What is not a function of skin?
a. Tough barrier against pathogens
b. Temperature control
c. Encourage water loss
d. Oil secretion
c. Encourage water loss
What is true about burns?
a. 1st degree burns involve the epidermis and dermis
b. Muscle and bone can be damaged in second degree burns
c. 3rd degree burns involve all three skin layers
d. 1st degree burns only involve the subcutaneous tissue
c. 3rd degree burns involve all three skin layers
What is not involved in culturing human skin epidermal cells?
a. Silver and iron supplements
b. An irradiated feeder layer (Swiss 3T3 J2 embryonic mouse fibroblasts)
c. Medium with cholera toxin, hydrocortisone, EGF, 10% foetal calf serum
d. Keratinocytes expand from the epidermis
a. Silver and iron supplements
What is a problem with current burn therapies?
a. Human cells are needed as feeder layers
b. Animal products, like serum, can carry pathogens
c. Only 10% of epidermal cells from the patient grow in culture
d. The culture skin cells can proliferate and lead to melanoma
b. Animal products, like serum, can carry pathogens
a. need mouse
c. (
What is a feature of CD34?
a. It is a cell surface marker on red blood cells
b. It can be found on haemopoietic stem cells and progenitor cells and hair follicle bulge region
c. Basal and super-basal bulge cells can regenerate hair follicles in the absence of CD34
d. It is unique to skin stem cells
b. It can be found on haemopoietic stem cells and progenitor cells and hair follicle bulge region
What is a feature of skin stem cells?
a. Transit amplifying cells are cycling and mostly basal
b. Early differentiation cells show intermediate long term proliferation
c. Transit amplifying cells are quiescent
d. Keratinocyte stem cells are present in large amounts
a. Transit amplifying cells are cycling and mostly basal
What is a feature of laminin10/11?
a. They repress the growth of stem cells
b. They are localised in the epithelial basement membranes
c. They can aid cell stem cell growth but do not impact tissue regeneration
d. They demonstrate that skin stem cells do not interact with the ECM
b. They are localised in the epithelial basement membranes
Which genes are expressed in the following types of stem cells?
a. Quiescent cells express epidermal differentiation markers
b. Cycling progenitor cells express Wnt inhibitors
c. Early differentiated cells express cell cycle progression genes
d. Cycling progenitor cells express genes for metabolic pathways
d. Cycling progenitor cells express genes for metabolic pathways
What is not a feature of pericytes?
a. They are localised to the epidermis
b. They can differentiates into fat, bone and cartilage
c. They Associate with basal keratinocytes and can promote epidermal cell proliferation from non-stem cells
d. They can restore adhesive structures (hemidesmosomes) and the basement membrane
a. They are localised to the epidermis
• Stem cells are responsible for organogenesis during embryonic and adult life.
T
• Third degree burns are the most painful.
F
• Cellular allografts are harvested from the patient themselves.
F
• Keratinocytes can be harvests and expanded to generate sheets and 3D cultures used to treat burns.
T
• A single haemopoietic stem cell can reconstitute the entire haemopoietic system of a mouse.
T
• Skin stem cells are found in the granular layer and are absent in hair follicles.
F
• Hair follicle epidermal stem cells in mice can be visualised as slow cycling cells in the bulge region.
T
What is a feature of colon epithelium?
a. There are no villi
b. There is an abundance of +4 stem cells
c. There is an absence of crypt based columnar cells
d. Paneth cells act as niche cells
a. There are no villi
What are the differentiated cell types found in intestinal epithelium?
a. Enterocytes secrete mucus
b. Goblet cells secret hormones
c. Enteroendocine cells are absorptive
d. Paneth cells are immune cells
d. Paneth cells are immune cells
How does Wnt signalling influence intestinal stem cells?
a. APC mutants demonstrate decreased Wnt signalling and a loss of CBC stem cells
b. Increased Wnt signalling can result in adenomatous polyps and colorectal carcinoma
c. An absence of Wnt signalling does not impact the intestinal stem cell pool
d. It down regulates Bmi1 markers to encourage +4 stem cell differentiation
b. Increased Wnt signalling can result in adenomatous polyps and colorectal carcinoma
What causes familial adenomatous polyposis?
a. An inactive Wnt signalling pathway
b. A mutation in APC
c. Under expression of Beta catenin
d. Constitutive production of APC
b. A mutation in APC
How can colorectal cancer be linked to stem cells?
a. Stem cells have no role in the development of colorectal cancer
b. When APC is lost in Transit Amplifying cells, rapidly proliferating adenomas develop
c. Knocking out APC in enterocytes leads to small adenomas that don’t progress
d. When APC is lost in CBC stem cells, rapidly proliferating adenomas develop
d. When APC is lost in CBC stem cells, rapidly proliferating adenomas develop
Which statement is correct?
a. Lgr5+ stem cells and Paneth cells do not interact
b. Paneth cells secrete Wnt and Notch ligands and Lgr5+ stem cells express Fzd7 and Notch 1 recptors
c. Lgr5+ stem cells produce daughter cells symmetrically and by independent choice
d. Lgr5+ cells are niche components that directly influence the activity of Paneth cells
b. Paneth cells secrete Wnt and Notch ligands and Lgr5+ stem cells express Fzd7 and Notch 1 recptors
What is evidence that crypt stem cell populations drift to clonality?
a. Confetti mice exhibited crypts labelled with a single fluoro chrome over a period of months
b. Confetti mice Lgr5 stem cells divided symmetrically and non-stochasitocally and always adopted the fate of a GFP labelled transit amplifying cell
c. Confetti mice exhibited villi labelled with a single fluoro chrome over a period of months
d. Confetti mice exhibited crypts and villi labelled with a single fluoro chrome over a period of months
a. Confetti mice exhibited crypts labelled with a single fluoro chrome over a period of months
How do Wnt and Notch signalling regulate intestinal stem cells?
a. Notch signalling causes Lgr5 and wnt expression in stem cells
b. Cells with high levels of delta activate notch and become absorptive
c. Delta-notch signalling results in lateral inhibition between adjacent cells
d. Wnt leads to the expression of lgr5 and notch in stem cells and down-regulation of Delta in Paneth cells
c. Delta-notch signalling results in lateral inhibition between adjacent cells
How does hedgehog and BMP signalling have a role in regulating the intestinal stem cell niche?
a. BMP4 is expressed in the crypt to repress Hh and Wnt signalling
b. Hh and Wnt signals from the crypt lead to BMP4 expression in the villus core
c. Disrupting hedgehog signalling can lead to ectopic crypts forming in the sides of villi
d. BMP4 expression in the villus core up regulates Hh and Wnt expression in the epithelium
b. Hh and Wnt signals from the crypt lead to BMP4 expression in the villus core
How can organoids self-organise into crypts?
a. Due to BMP4 mediated crypt cell induction
b. Organoids swell when exposed to Forskolin and the addition of exogenous wnt influences crypt formation
c. Paneth cells secret wnt which induces neighbour cells to express EphB which repulse cells expressing EphrinB
d. Paneth cells secrete Delta which can degrade Lgr5+ markers and encourage crypt cell differentiation
c. Paneth cells secret wnt which induces neighbour cells to express EphB which repulse cells expressing EphrinB
• The intestinal epithelium is the slowest tissue to regenerate.
F
• Epithelial cell migration from the crypt to vilus takes 10-15 days.
F
• In the stem cell zone model, it is proposed that transit amplifying cells can de-differentiate back to stem cells.
T
• +4 stem cells are marked with Bmi1 and CBC stem cells are marked with Lgr5.
T
• Lgr5 positive cells can only generate enterocytes and goblet cells.
F
• Lgr5+ stem cells can only build crypt villus structures in vitro if a mesenchymal niche is present.
F
• Culture organoids have been used to repair damage caused by colitis in the intestinal epithelium of mice.
T
What is involved in epithelial-mesenchymal transition?
a. Mesenchymal cells are 100% individualistic
b. An extreme example of EMT is epithelial wound healing
c. Morphogenesis is a pathological form of EMT
d. The removal and repair of cells is a normal role of EMT
d. The removal and repair of cells is a normal role of EMT
What occurs during EMT progression?
a. Cell junctions develop as cadherin expression increases
b. Basal lamina adhesion is lost
c. Intersital ECM is degraded
d. Basal lamina is synthesised
b. Basal lamina adhesion is lost
Which family contains EMT transcription factors?
a. Snail
b. Cadherin
c. Myc
d. Sox
a. Snail
Which are features of mesenchymal cells?
a. Up regulation of EcadH, Apico basal polarity, down regulation of proteases
b. Up regulation of basal lamina ECM, front back polarity, down regulation of E cadherin
c. Down regulation of E cadherin, Up regulation of interstitial ECM, front back polarity
d. Up regulation of proteases, up regulation of basement membrane, up regulation of cytokeratins
c. Down regulation of E cadherin, Up regulation of interstitial ECM, front back polarity
What are the types of EMT?
a. Type 1 describes normal morphogenesis and foetal development processes
b. Type 2 describes the development of cancer cells
c. Type 3 describes processes in wound healing, inflammation and fibrosis
d. Type 4 describes processes leading to angiogenesis
a. Type 1 describes normal morphogenesis and foetal development processes
What can occur during solid tissue cancer?
a. Secondary tumours are easily removed with surgery
b. Tumour initiating cells develop into circulating tumour cells
c. EMT can result in cells being resistant to apoptosis
d. Chemotherapy can remove cancer stem cells
c. EMT can result in cells being resistant to apoptosis
What can solid cancer progression resemble?
a. Clonal expansion resembles stem cell progression
b. EMT to MET is resembled by cell proliferation extension
c. ECM alterations resemble stem cell development
d. Differentiation resembles EMT to MET
a. Clonal expansion resembles stem cell progression
What are the CSC models?
a. The dedicated model states that many cells in a cancer population are capable of becoming TIC/CSC
b. The part time model states that the TIC count is always low
c. The dedicated model states that there is a small amount of CSC proportion in the tumour
d. The part time model states that the niche does not influence CSC regression
c. The dedicated model states that there is a small amount of CSC proportion in the tumour
• Mesenchymal cells lack apical basal polarity.
T