Somites derive from the __________ and neural crest cells derive from the ___________.

A. Ectoderm, endoderm

B. Mesoderm, endoderm

C. Endoderm, ectoderm

D. Mesoderm, ectoderm

Question 2

The rostral - caudal axis is the same as the:

A. Anterior - posterior

B. Dorsal - ventral

C. Left - right

D. None of the above

Question 3

Notch and ephrin are examples of

A. Paracrine factors

B. Endocrine factors

C. Juxtacrine factors

D. They are not involved in cell signaling

Question 4

Neural crest cells can receive signals that shape their path or their fate from:

A. Other neural crest cells

B. The cells they are passing by

C. The extracellular matrix

D. The cells at their destination

E. All of the above

Question 5

The back musculature is formed by the:

A. The abaxial myotome

B. The primaxial myotome

C. The dermatome

D. The sclerotome

Question 6

If you generated a mutation that sped up the rate at which the node moves toward the posterior, what effect would it have on somite formation?

A. The somites formed would be shorter than normal

B. The somites formed would be longer than normal

C. The somites formed would be normal

D. The somite would not separate from the presomitic mesoderm

Question 7

1. Cells of newly-formed somites are initially:

A. Mesenchymal

B. Epithelial

C. Ectodermal

D. Endodermal

Question 8

You transplant thoracic somites from a donor chicken embryo into the area containing cervical somites in a recipient chicken embryo. The donor chicken later grows ribs from its neck vertebrae. Since ribs are a structure formed from thoracic somites you conclude that the thoracic cells you transplanted are:

A. Neither specified or determined

B. Specified but not determined

C. Determined

D. None of the above

Question 9

If you made a mutation where cells of the somite constantly make the protein Noggin, which of the following would you expect to see?

A. An increase in neural crest cell mesenchymal to epithelial transition

B. A decrease in neural crest cell mesenchymal to epithelial transition

C. An increase in neural crest cell epithelial to mesenchymal transition

D. A decrease in neural crest cell epithelial to mesenchymal transition

Question 10

In trunk neural crest cells, the switch between neural precursors and melanoblast precursors is controlled by:

A. The FoxD3 transcription factor

B. The MITF transcription factor

C. The ephrin receptor

D. The Kit receptor