Midterm 3-3 Flashcards
(21 cards)
What is gastrulation
it is the migration of cells that organize the blastula to more organized cell types. This begins after cleavage
In the blastula what are the cell types (give an example of what they make
Ectoderm (skin and nerve cells)
mesoderm (organs muscles)
Endoderm (gut plus other organs)
What are the steps of gastralation
A blastapore forms on the surface of the blastomere, where the cells will then migrate and form and invagination. Cells will then migrate inward and shrink the blastocoel creating the three germ layers.
What are the body axes
these are all established as the embryo moves through development, there is the anterior, posterior, dorsal, ventral
What is organogenesis. What does it involve
the process of forming organs. This involves cell differentiation (differential gene expression) and cell proliferation
What is morphogenesis
The assembly of cells into recognizable tissue
What is Determination
a cells irreversible commitment to a particular cell type
What is differentiation
When you have the final cellular diversity that is made through differential gene expression
What is the chronology of development
Pattern formation to morphogenesis to determination to differentiation
What does the mesoderm form early in development and what does it do
It will form the notochord which will be on the dorsal side of the embryo. It will organize the body plan and will later on by destroyed by programmed cell death
How is the neural tube formed
Signals from the notochord will stimulate the ectoderm on the dorsal side to form the neural tube
What does the neural tube emit
a molecular signal that organizes the nearby mesoderm cells into somites allowing the neural tube to then be surrounded by somites
What does the fate of the somyte rely on
the cell cell signals that are initiated by nearby tissue
Distinguish between differentiated and determined somytes
If they are just have a differentiated fate and if a section of the somyte is moved to another, then it will form normally, but if something is determined, then the transplanted somyte piece will move form what it would have formed before it was transplanted
How do signal affect somites
The somite receives surrounding molecular signals form tissue where the expression of the stomyte is initiated by the signals in the tissue and it results in the development of specialized cells
When are muscle cells differentiated
when the cells express genes specific to that cell type
What are the categories of segementation
maternal genes, gap genes, pair-rule genes, segment polarity genes
What are maternally expressed morphogens
they are genes that are expressed maternally and the mRNAs are deposited within the egg. Once fertilizatioon of the egg happens, these mRNAs are translated, generating morphogens, such as bicoid
What are gap genes
if there was a loss of function here, it will result in the loss of several consecutive segments in fly embryos
What is the Pair rule genes
this brings in alternating segments in the embryo. They are critical in the formation of every segment
What are semgment polarity genes
they are important in the formation of components of each segment
