Question

cell and Tissue Engineering question. pls answer fast . Thanks

Part A. True or False (4 points) A.1. In general, tens of millions of cells are required to construct a functional tissue. Obtaining adequate cells is a big challenge to engineer a piece of bioartificial cartilage because primary adult chondrocytes don't grow in vitro. ) A.2. Mesenchymal cells (e.g. fibroblasts) surrounded by ECM (e.g. collagen IV) are not mainly responsible for soft organ-specific functions (e.g. small intestine function, kidney function). A.3. Healthy adult human cells usually don't proliferate, or die unless diseases occur. ) A.4. Embryonic stem cells are not totipotent and cannot infinitely self-renew. A.5. For highly adhesive surface, cells can achieve maximum migration speed only if the ligand concentration on the substrate is low. A.6. In the case of cell-ECM signaling, small peptide fragments (e.g. RGD) of ECM molecules bind to the receptors (e.g. integrins) on cell membranes. ) A. 7. DNA microarrays and DNA samples extracted from cells/tissues are used in biomarker discoveries of diseases at gene levels. A.8. One of the biggest challenges of applications using iPS or ES cells is how to avoid tumorigenesis during tissue regeneration.

Answer 1

answer 1: it is not true because the primary chondrocytes can grow invitro in a three dimensional biodegradable scaffolds during the cartilage formation.

answer 2: true that the mesenchymal cells surrouded by the ECM are not responsible for soft organ specific function because the mesenchymal cells are the multipotent and they have multiple potecy to be differentiated into any of the cells and they have a role in the repairing. fibroblast is a cell that synthesizes the extracellular matrix and collagen, produces the structural framework (stroma) for animal tissues, and plays a critical role in wound healing.

answer3: false because the healthy human cells proliferate and give rise to the new cells and they can die natural death and can die from disease as well.

answer4: true that embroyonic cells are not totipotent and they cant renew .

answer5: false this is because the many studies state that the maximum migration speed of the cells were found when there was an intermediate conc. of the ligand and substrate .

answer6: true because in the cell - ECM interaction , the integrin receptor on the cells interact with ECM matric rgd conserved sequence and lead to the signalling cascade.

answer7: true because microarray like studies can be used to study the extent to which certain genes are turned on or off in cells and tissues.

answer8: true because tumoriogenesis is one of the problem in the application of the ips cell and ES and this can be solve by the irradiation.