There are three main ways in which inducing signals may be passed between cells EXCEPT

#Question id: 7225

#Unit 5. Developmental Biology

The processes by which the three ectodermal regions are made physically and functionally distinct from one another is called neurulation. Following statements are regarding to the mechanism of neurulation.

A. The specification of the ectoderm is accomplished during gastrulation, primarily by regulating the levels of BMP experienced by the ectodermal cells.

B. High levels of BMP specify the cells to become neural plate.

C. Very low levels specify the cells to become epidermis.

D. Intermediate levels effect the formation of the neural crest cells.

Which of the following combination is correct?

#Question id: 7226

#Unit 5. Developmental Biology

Experimental evidences suggest that control of proximal-distal specification of the limb is correlated with the age of the progress zone mesenchyme. Match the following experiment (Column I) with their results (Column II).

#Question id: 7227

#Unit 5. Developmental Biology

The regulative ability of the limb bud has recently been highlighted by a remarkable experiment of nature. In numerous ponds in the United States, multilegged frogs and salamanders have been found. The presence of these extra appendages has been linked to the infestation of the larval abdomen by parasitic trematode worms. The eggs of these worms apparently split the developing tadpole limb buds in several places, and the limb bud fragments develop as multiple limbs. This shows:

A. The limb field represents a harmonious equipotent system. 

B. The limb field do not represents harmonious equipotential system because different types of genes express during proximal to distal growth.

C. The limb field represents coupled system wherein one gene maintain the expression of other genes.

D. The limb field represents a harmonious equipotent system because only Hox genes expresses all along the limb axis.

E. The limb field represents cells of the limb region can be instructed to form any part of the limb. 

Which of the following statements are correct?

#Question id: 7228

#Unit 5. Developmental Biology

Why do Drosophila wings develop in only one particular thoracic segment, legs in all three, and antennae on the head? Which of the following answer is correct?

#Question id: 7229

#Unit 5. Developmental Biology

Two embryos were injected with bicoid at early cleavage stage. What would be the phenotypes of the resulting embryos?

#Question id: 7230

#Unit 5. Developmental Biology

Following statements are being made regarding gradients of specific translational inhibitors in drosophila.

A. In the anterior region, Bicoid protein prevents translation of the caudal message by binds to a specific region of caudal’s 3′UTR. Here, bicoid recruits Bin3 (a translation inhibitor) which prevents translation of caudal in the anterior of the embryo.

B. In the posterior region, Nanos protein prevents translation of the hunchback message by forming a complex with several other ubiquitous proteins, including Pumilio and Brat. This complex binds to the 3’UTR of the hunchback message, where it recruits d4EHP and prevents the hunchback message from attaching to ribosomes.

C. In the anterior region, Bicoid protein prevents translation of the caudal message by binds to a specific region of caudal’s 5′UTR. Here, bicoid recruits pumilio and brat (a translation inhibitor) which prevents translation of caudal in the anterior of the embryo.

D. In the posterior region, Nanos protein prevents translation of the hunchback message by forming a complex with several other ubiquitous proteins, including bin3 and smaug. This complex binds to the 3’UTR of the hunchback message, where it recruits d4EHP and prevents the hunchback message from attaching to ribosomes.

Which of the following combination are incorrect?