Cell Movement Quiz

Question 1

Invagination

Answer 1

Inward bending of a sheet of tissue.

Question 2

Example of Invagination

Answer 2

Formation of the digestive tube {archenteron}

Question 3

What must be true to start off invagination?

Answer 3

Apical Constriction

Question 4

How does apical constriction work?

Answer 4

Actin and myosin contract at one end of the cells, pinching them. Adhesive connections also involved

Question 5

Another example of apical constriction

Answer 5

Closure of the Neural Tube

Question 6

Epiboly: General definition, and example

Answer 6

Spreading of a sheet of tissue. E.g the ectoderm spreading and surrounding the inner cells

Question 7

Radial Intercalation

Answer 7

A double sheet of cells combine into one sheet, expanding the surface area in all 4 directions tangent to the sphere.

Question 8

Involution [general definition and example]

Answer 8

When a sheet of tissue rolls around an edge. Example when cells move around the lip of the blastopore

Question 9

Ingression [general definition, example, and what must happen]

Answer 9

Detachment of single cells from a sheet of tissue, example primary mesenchyme in the sea urchin gastrula, cells must cease connections with each other

Question 10

What does EMT mean, and what is it associated with?

Answer 10

Means “epithelial to mesenchymal transition”, and is associated with ingression

Question 11

Delamination

Answer 11

Involves splitting of one sheet of tissue to form two

Question 12

Convergent Extension

Answer 12

Directed rearrangement of cells to shorten a tissue along one axis [convergence] while lengthening along the orthogonal axis [extension]

Question 13

What are some examples of convergent extension?

Answer 13

marginal zone cells in frog, germ band in flies, and archenteron in sea urchins.