Question

What is a cellular blastoderm?

Answer 1

Cellular blastoderm:

1. After fertilization, the zygote nucleus is formed by the fusing of sperm and egg nuclei, which undergoes a series of rapid and synchronous divisions.
2. The cytoplasm remains undivided while the nucleus keeps undergoing divisions.
3. This leads to the formation of a syncitium composed of a multinucleate single cytoplasm.
4. Membranes develop inwards from the cell surface to enclose the nuclei toward the end of the 13th division.
5. Cellularization is a large-scale form of cytokinesis that leads to the creation of a layer of approximately 6,000 cells beneath the embryo's surface.
6. This is the cellular blastoderm.
7. Morphogenetic movements soon begin and the blastula forms a gastrula with distinct epiderm, mesoderm, and hypoderm.