Mutations that block expression of the E-cadherin gene are thought to be an important step in metastasis. To better understand how loss of E-cadherin contributes to metastasis, scientists created two cell lines that differed in their expression of E-cadherin. One cell line expressed normal E-cadherin, but at 10% of the usual levels. The other cell line expressed normal E-cadherin at the usual levels, and also, at high levels a mutant form that included the cytoplasmic domain but lacked the rest of the protein. Both cell lines exhibited strongly reduced cell adhesion in culture. However, only the cell line with reduced expression of normal E-cadherin metastasized when introduced into mice.

Which of the following hypotheses is most consistent with the observations on cell adhesion and metastasis in these cell lines?

TLS Online TPP Program

#Question id: 15422

#Unit 5. Developmental Biology

During Vulval induction in C. elegans, the anchor cell secretes, a paracrine factor which receives by VPCs and become vulva. If the anchor cell is destroyed, the VPCs will not form a vulva. This is the example of:

TLS Online TPP Program

#Question id: 15420

#Unit 5. Developmental Biology

signal from the inducing cell is necessary for initiating new gene expression in the responding cell. Without the inducing cell, the responding cell is not capable of differentiating in that particular way, phenomena known as:

TLS Online TPP Program

#Question id: 15419

#Unit 5. Developmental Biology

Doris Taylor’s research group used detergents to remove all the cells from a cadaveric rat heart, which leaves behind the natural extracellular matrix. An extracellular matrix scaffold can promote the differentiation and rebuilding of a beating heart. The researchers then infused this ECM scaffold with cardiomyocytes. Now these cells differentiated and organized into a functionally contracting “recellularized” heart. Which of the following statement is correct?

TLS Online TPP Program

#Question id: 15418

#Unit 5. Developmental Biology

In which type of interaction, the responding tissue has already been specified and needs only an environment that allows the expression of particular traits?

TLS Online TPP Program

#Question id: 15417

#Unit 5. Developmental Biology

Sequence of amphibian lens induction postulated by experiments on embryos of the frog Xenopus laevis ; EXCEPT

TLS Online TPP Program

#Question id: 15416

#Unit 5. Developmental Biology

Which of the following statements are regarding to lens induction in xenopus is incorrect?