The origin of the craniates occurred at roughly the same time as the

TLS Online TPP Program

#Question id: 14836

#Unit 5. Developmental Biology

In the case of the French flag model. we assume a source of morphogen at one end and a sink at the other and that the concentrations of morphogen at both ends are kept constant but are different from each other. If the cells can respond to threshold concentrations of the morphogen, Thresholds can represent the

a. amount of morphogen that must bind to receptors to activate an intracellular signaling system. 

b. concentrations of transcription factors required to activate particular genes.

c. concentration at any point effectively provides positional information.

d. amount of morphogen that must bind to receptors to inactivate an extracellular signaling system.

TLS Online TPP Program

#Question id: 14837

#Unit 5. Developmental Biology

Each of the three major strategies of cell specification summarized in TABLE  offers a different way of providing each embryonic cell with a set of determinants (often transcription factors) that will activate specific genes and cause the cell to differentiate into a particular cell type:

Choose right combinations;

TLS Online TPP Program

#Question id: 14838

#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: 14839

#Unit 5. Developmental Biology

Given are certain facts which define ‘specification’ of a developing embryo.

 A. At the specification stage, commitment to cell identity is labile.

 B. At the specification stage, cell is capable of differentiating autonomously.

 C. The cell “knows” very early what it is to become without interacting with other cells.

 D. A phase where inductive signals trigger cell to determines their fate.

 Which of the above statements best define specification?

TLS Online TPP Program

#Question id: 14840

#Unit 5. Developmental Biology

If a cell or tissue type is able to differentiate according to its specified fate, it is assumed that commitment is:

TLS Online TPP Program

#Question id: 14841

#Unit 5. Developmental Biology

How cells became different from one another during embryonic development?