Tag: Early Development in Animals

67. In the avian embryo, the blastocoel-like fluid-filled cavity is formed between: (1) epiblast and hypoblast (2) hypoblast and yolk (3) primary hypoblast and secondary hypoblast (4) Koller’s sickle and […]

The early embryonic development in amphibians and aves serve as two different model plans of development. In the former the germ layer formation is initiated from a fluid-filled ball like […]

65. The major structural characteristic of avian gastrulation is the primitive streak, which becomes the blastopore lips of amniotic embryos. Migration through the primitive streak is controlled by Fgf8. What […]

Following statements were made about the events occurring during chick development. A. The fertilized chick egg undergoes discoidal meroblastic cleavage; however the cleavage does not extend into the yolk cytoplasm. […]

Hensenis node is established as the avian equivalent of the amphibian dorsal blastopore lip. The following observations are presumed to be support of the same. A. It is the region […]

The part of the embryo from which the ectoderm, mesoderm and endoderm are formed in chick is known as (1) primitive streak (2) hypoblast (3) epiblast (4) cytotrophoblast Introduction In […]

Cells from an early frog blastula were remove from the animal pole and used to replace cells from the vegetal pole of the blastula. The following events may be expected. […]

In an experiment, activin-secreting beads were placed on unspecified cells from an early Xenopus embryo. The activin then diffused from the beads. If the beads contained 1nM of activin, it […]

59. A “morphogen” can determine the fate of a cell by its concentration. Given below are some statements on the experiment performed to study the gradient- dependent effect of the […]

In Xenopus, the Noggin protein, accomplishes two major functions of the organizer: it induces dorsal ectoderm to form neural tissues, and it dorsalizes mesoderm cells. Which one of the following […]