Question

Blastopore is found is-
A. Gastrula
B. Blastula
C. Morula
D. Neurula

Answer 1

Blastopore is the opening of archenteron which is mouth like. It is developed at the time of gastrulation. Blastopore may become the mouth of an animal and the second opening may become the anus (second opening is called Deuterostome).

Complete answer:
-After the formation of the zygote, it divides by the process of cleavage and forms a structure called Blastula. The blastula is a hollow sphere which contains a fluid-filled cavity called “Blastocoel”. This cavity is enclosed by a layer of cells called “Blastoderm”.
-From here, the development of the second stage of the embryonic development starts, the process is called- Gastrulation. The hollow sphere- blastula, further divide and form a structure called “Gastrula”. It is composed of two or more layers of cells of the germinal layer. This stage has three layers of cells. In gastrulation, the cells of blastula rearrange themselves to form three main layers. Each of the layers is named as the germ layer which further builds or differentiate into different types of an organ system.
-The outermost layer is known as – Ectoderm, followed by the cavity of blastocoel, the second layer- Endoderm followed by the cavity known as Archenteron.
-This cavity of gastrula communicates with the outside environment with the help of a pore known as “Blastopore”. After the maturation of some animals, this part of gastrula might develop into a mouth or an anus.
-Whereas, morula is the name given to the sixteen celled structure, made during the initial development of the early-stage embryo. This stage is also called “Blastomere”.
-Following gastrulation, “Neurulation” stage is followed. In this stage, the neurula is formed. This is one of the most important developmental stages as the building of the brain and spinal cord and development of the whole nervous system take place through this stage.

Hence, the correct answer is option (A).

Note: The blastula is a single-layered structure of a cell which is filled with a fluid-filled cavity (blastocoel) and this structure differentiates into “Gastrula”. Gastrula is a stage where cells, which were not in contact with each other before, now interact with each other resulting information of three different types of layers. This structure now further differentiates and follows the stage of “Neurulation” in which bending of the neural plate results in the formation of a hollow tube. This hollow tube now develops into the brain and spinal cord forming the central nervous system.