Following statements are regarding to the CFTR.

A. cystic fibrosis transmembrane conductance regulator allows Cl− ions to flow out of the cell, following their concentration gradient.

B. ATP binding to CFTR’s two nucleotide-binding domains appears to close the Cl− channel, and the hydrolysis of one ATP opens it (the other ATP remains intact).

C. the CFTR channel can open only if its regulatory domain (which is unique among ABC transporters) has been phosphorylated, thus regulating the flow of ions across the membrane.

D. The maintenance of electrical neutrality requires that the Cl− ions transported by the CFTR be accompanied by positively charged ions, mainly Na+. The transported ions are osmotically accompanied by water, thus maintaining the proper level of fluidity in secretions of the airways, intestinal tract, and the ducts of the pancreas, testes, and sweat glands.

Which of the following combination is correct?

#Question id: 7274

#Unit 5. Developmental Biology

The following experiment is designed to study the role of several hormones in the regulation of metamorphosis in frogs.

 If the thyroid gland were removed from the tadpoles in Group 3, metamorphosis would

#Question id: 7273

#Unit 5. Developmental Biology

Hox9 and Hox10 paralogues specify the stylopod, Hox11 paralogues specify the zeugopod, and Hox12 and Hox13 paralogues specify the autopod. This scenario has been confirmed by numerous experiments.

Which of the following experiment correctly describe this scenario?

#Question id: 7272

#Unit 5. Developmental Biology

Few statements regarding the role of disheveled (dsh) and beta-catenin in the development of sea urchin.

A. beta-catenin accumulates predominantly in the macromeres and somewhat in veg2 tier cells.

B. At the fourth cleavage disheveled and β-catenin, both of which are found in the cytoplasm and are inherited by the micromeres.

C. Treating sea urchin embryos with lithium chloride allows β-catenin to accumulate in every cell and transforms presumptive ectoderm into endoderm.

D. When β-catenin is prevented from entering the nuclei (i.e., it remains in the cytoplasm), the vegetal cell fates are specified, and the entire embryo develops as a ciliated ectodermal ball.

Which one of the following options represents a combination of correct statement?

#Question id: 7271

#Unit 5. Developmental Biology

In drosophila, Head formation required higher Bicoid concentrations than thorax formation, because

#Question id: 7270

#Unit 5. Developmental Biology

According to this figure which of the following option is incorrect?

#Question id: 7269

#Unit 5. Developmental Biology

Following statements are regarding to gastrulation in chick embryo.

A. During gastrulation, future mesodermal and endodermal cells migrate from the epiblast through the primitive streak into the interior of the blastoderm.

B. An aggregation of cells, known as Hensen’s node, forms at the posterior end of the streak.

C. As the streak extends, cells of the epiblast move toward the primitive streak, through it, and then outward again underneath the surface to give rise internally to the mesoderm and endoderm, the latter displacing a lower layer of cells called the endoblast.

D. Cells that remain in the epiblast form the endoderm.

Which of the following statements are correct?