The ability of a population of fibroblasts to migrate along the surface of a tissue culture dish depends on adhesion between the cell surface and the extracellular matrix molecules coating the dish. The dish is coated with laminin, and the only cell-surface protein capable of binding laminin is a cell-adhesion protein called an integrin. Integrins are integral plasma-membrane proteins that function as heterodimers. Under these conditions the rate at which a fibroblast can migrate along the laminin coated culture dish is proportional to the strength of adhesion between the cell and the laminin substrate. The table below lists the rate of cell migration observed for fibroblasts genetically engineered to generate the indicated phenotypes.

 Which of the following is the most likely explanation for failure of overexpression of the integrin alpha subunit to alter the rate of fibroblast migration?

#Question id: 1533

#Unit 4. Cell Communication and Cell Signaling

Why might using retroviral vectors for gene therapy increase the patient's risk of developing cancer?

#Question id: 1534

#Unit 4. Cell Communication and Cell Signaling

Cadherin proteins help animal cells stick (adhere) to each other. Choose which statement about cadherin in cancer cells that are metastasizing (spreading) throughout a patient's body is most likely correct.

#Question id: 1535

#Unit 4. Cell Communication and Cell Signaling

Following statements are regarding to cancer stem cell (CSCs).

a. A representative subpopulation of cancer cells with peculiar molecular aspects that resemble some of those typical of normal stem cells.

b. These cells are capable of replenishing the repertoire of identical cancer cells.

c. These cells cannot create heterogeneous progeny that differentiate into more mature cells.

d. These cells show extraordinary proliferative potential.

e. These cells show excessive programmed cell death.

Which of the following combination is correct?

#Question id: 1536

#Unit 4. Cell Communication and Cell Signaling

Use the following figure to answer the question. According to figure, which of the following statement is incorrect?

#Question id: 1537

#Unit 4. Cell Communication and Cell Signaling

Transformation of mature cells may also occur due to aberrant expression of stemness genes, resulting in cell clones with a dedifferentiated phenotype and self-renewing capacity resembling stem cells. Recent experimental evidence supporting this proposal has been provided with the induction of adult somatic cells into pluripotent stem (iPS) cells through ectopic expression of four genes encoding the pluripotency factors Oct4 and Sox2, the transcription factor Klf4, and the oncoprotein c-Myc in mouse or human fibroblasts. However, along with pluripotency comes the capability of generating teratomas. On the basis of the above information which of the following outcome is most appropriate?

#Question id: 1538

#Unit 4. Cell Communication and Cell Signaling

Many aspects of the biology of stem cells, including maintenance of pluripotency, self-renewal, and differentiation, are controlled by the phenomenon of RNA interference involving a variety of small molecules of RNA.

Match the following miRNA (Column I) with their target gene (Column II).