GRE Subject Test: Biochemistry, Cell, and Molecular Biology : Help with Developmental Stages
Study concepts, example questions & explanations for GRE Subject Test: Biochemistry, Cell, and Molecular Biology
All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
Example Questions
Example Question #1 : Help With Developmental Stages
The mesodermal germ layer can give rise to each of the following cell types except __________.
myoblasts
alveoli
the notocord
fibroblasts
alveoli
The mesoderm gives rise to the "middle" cells that line the body, such as the muscle. The notocord is a critical embryonic structure that forms from the mesoderm, and myoblasts and fibroblasts are cells that line the body. The alveoli are part of the lung, which originates from the endodermal germ layer.
Example Question #2 : Help With Developmental Stages
Which of the listed processes are part of gastrulation?
The invagination of the notochord to induce the formation of the neural plate
The formation of the primitive streak that undergoes epithelial to mesenchymal transition
The ingression of cells from the epiblast to form a circular blastocyst
The formation of ectoderm and endoderm germ layers in radially symmetric organisms
The formation of the primitive streak that undergoes epithelial to mesenchymal transition
Gastrulation is the process of cells from the epiblast ingressing into the embryo to form the three germ layers of bilaterally symetrical animals. When gastrulation is complete, the embryo is referred to as a gastrula. The group of cells that lead the migration of cells into the embryo are called the primitive streak, and they undergo epithelial to mesenchymal transition to be able to migrate. You can image the epithelium as many tightly packed squares. Becomimg mesenchymal turns these cells into more malleable stage, like a soft cushion. They can then "drop" into the inner layer of the blastocyst and lead the process of gastrulation.
Example Question #3 : Help With Developmental Stages
Which of the following statements about determination is true?
Determination follows differentiation
Once determined, a cell changes its appearance
Determination occurs after two cell divisions in most organisms
The pattern of transcription is the same in a differentiated cell as it is in a determined cell
No matter where its placed in an embryo, a determined cell will keep its determination
No matter where its placed in an embryo, a determined cell will keep its determination
Determination is the process of a cell committing to a particular fate and is influenced by the cell's environment as well as its own genome. It's not possible to tell the difference between an undetermined and a determined cell since determined cells do not change in appearance. After determination comes differentiation. Differentiation results from differential gene expression (transcription, mRNA splicing, and translation).
Example Question #4 : Help With Developmental Stages
Which of the following terms describes when the single germ layered blastula reorganizes into a structure with mesoderm, endoderm, and ectoderm germ layers?
Morphogenesis
Myogenesis
Blastulation
Somiteogenesis
Gastrulation
Gastrulation
The correct answer is gastrulation. Gastrulation occurs through five stages (1. invagination 2. involution 3. ingression 4. delamination 5. epiboly) and results in the formation of a gastrula with the mesoderm, endoderm, and ectoderm germ layers. Blastulation is the formation of the single germ layered blastula, which is a process that precedes gastrulation. Somiteogenesis forms somites in developing embryos to give rise to the future spine. Myogenesis is the formation of muscle tissue. Morphogenesis is the process of an organism forming its shape, driven by cell cycle progression, differentiation, and subsequent development of organs and appendages.
Example Question #4 : Differentiation
Which embryonic structure is created by the process of gastrulation?
The notochord
The neural tube
The epiblast
The mesoderm
The mesoderm
Gastrulation is a process occurring in week three of development. At this time, the epiblast will further differentiate into three germ layers: the ectoderm, the mesoderm, and the endoderm. As a result, we can say that gastrulation allows for the creation of the mesoderm.
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All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
