Midterm 2

Question 1

At the 60 cell stage, are cells specified or determined?

Answer 1

Specified

Question 2

When is A/P determined?

Answer 2

Oogenesis

Question 3

Which region is the important organizer?

Answer 3

Vegetal

Question 4

What do cells from the animal half mainly form?

Answer 4

Ciliated Ectoderm

Question 5

What do cells from the vegetal half mainly form?

Answer 5

Gut and Skeletal elements

Question 6

What is the Candidate Gene Approach?

Answer 6

Look at other organisms and see if there are proteins known to act as inducers

Question 7

What does Li block and what pathway does it mimic?

Answer 7

GSK-3 Kinase which is responsible for the degradation of beta - catenin. It mimics the wnt/wingless signaling.

Question 8

What kind of fate does beta-catenin promote in sea urchins?

Answer 8

Vegetal Fate

Question 9

What family does Nodal belong to?

Answer 9

TGF-beta

Question 10

What expression of Nodal does it lead to?

Answer 10

Expresses specific genes in oral ectoderm such as goosecoid, BMP2/4

Question 11

What inhibits Nodal?

Answer 11

Lefty

Question 12

FGF, Receptor, and Function

Answer 12

Maintenance of mesoderm formation

FGF Receptor

Question 13

EGF, Receptor, and Function

Answer 13

EGF Receptros

Cell proliferation and differentiation

Question 14

TGF-beta, Receptor, and Function

Answer 14

Type 1 and 2

Mesoderm Induction and Patterning

Question 15

Wnt-8c and Vg1 induces what?

Answer 15

Nodal expression so it can set up the organizing center.

Question 16

What is required for the formation of the primitive streak and Hensen’s node?

Answer 16

FGF+Nodal+Chordin

Question 17

What prevents the primitive streak from happening?

Answer 17

Signals from the hypoblast. Only when the hypoblast is replaced by the endoblast will a primitive strek form.

Question 18

Cdx2 and Oct 3/4

Answer 18

Blastocyst stage Cdx2 is expressed in the trophectoderm and Oct3/4 expressed in ICM.