Question 1

Which of these statements is true of cells moving through the primitive streak of a chick or a mouse embryo?

Accepted Answer

A)  Cells become mesenchymal in nature. 
B)  Cells maintain their epithelial nature. 
C)  Cells strengthen adherens junction complexes. 
D)  Cells maintain their tightly packed organization. A

Question 2

Which of the following results from a failure to close the neural tube in the fore- and midbrain regions?

Accepted Answer

A)  Rachischisis 
B)  Craniorachischisis 
C)  Anencephaly 
D)  Spina bifida C

Question 3

Which of the following does not play a role in the formation of a blastocoel?

Accepted Answer

A)  Sodium 
B)  Osmosis 
C)  Tight junctions 
D)  Apoptosis D

Question 4

Which of the following is not associated with the differential adhesion hypothesis?

Accepted Answer

A)  Cells sort according to differences in adhesiveness and surface tension 
B)  Cells sort similarly to molecules of two immiscible liquids 
C)  Cells sort according to the types and numbers of cell-adhesion molecules 
D)  Cell sorting recapitulates the final positions of cell layers in the normal embryo.

Question 5

What is the family of cell-adhesion molecules that require calcium to adhere to the same molecules on another cell?

Accepted Answer

A)  Cadherins 
B)  CAMs 
C)  Integrins 
D)  Laminins

Question 6

What is the ectodermal interface between non-neural ectoderm and the neural plate during neurulation called?

Accepted Answer

A)  Neural fold 
B)  Neural crest 
C)  Neural furrow 
D)  Neural groove

Question 7

Which of the following cell movements involves remodeling of intercellular junctions to guide medio-lateral intercalation?

Accepted Answer

A)  Delamination 
B)  Involution 
C)  Epiboly 
D)  Convergent extension

Question 8

What is the subcellular event that provides the force required for puckering the epithelium during invagination?

Accepted Answer

A)  Inhibition of myosin motor activity 
B)  Activation of Snail protein 
C)  Endocytosis of cadherins 
D)  Asymmetric actin-based contraction

Question 9

Which of the following embryonic cell movements involves the separation of cells from a continuous sheet of cells?

Accepted Answer

A)  Ingression 
B)  Involution 
C)  Epiboly 
D)  Convergent extension

Question 10

The first cleavage event in a C. elegans embryo gives rise to two differently sized cells with different content and fates. What is this type of cell division called?

Accepted Answer

A)  Asymmetric division 
B)  Symmetric division 
C)  Radial division 
D)  Spiral division

Exam 7: Morphogenesis: Change in Form in the Early Embryo