Embryogenesis in sea urchins Flashcards
What is the pattern of cleavage in sea urchins?
radial holoblastic cleavage with isolecithal yolk
Define macromeres
large cells
Define mesomeres
medium cells
Define micromeres
small cells
Define vegetal pole
- Cells with most yolk, less division
2. makes mesoderm
Define animal pole
- cells with more nuclei and division, little yolk
2. Makes ectoderm
What pole of the developing blastomere is associated with mesoderm formation?
Vegetal pole
What pole of the developing blastomere is associated with ectoderm formation?
Animal pole
What is the role of micromeres?
organizers of development, similar to grey crescent region we have seen in earlier examples. They change the fate of surrounding cells
What is a blastomere
a cell formed by cleavage of a fertilized ovum.
When looking at a blastomere with the animal pole on top and vegetal pole on the bottom, what side is the oral side?
The left side, with the right side being aboral
Define a double negative gate
Gene A inhibits Gene B, which prevents Gene B from inhibiting Gene C, activating Gene C.
Define feed forward circuit
Gene A creates a product that partially activates Gene C, but also activates Gene B, which works in conjunction with Gene A to activate Gene C.
What is Beta-catenin
a dual function protein, involved in regulation and coordination of cell–cell adhesion and gene transcription
