exam 4

Question 1

Amphibian b-catenin activity becomes stabilized at a site opposite that of sperm entry..

Question 2

Formation of the amphibian Organizer involves high level expression of

Answer 2

high nodal: high Xnr on dorsal ( high translation of Vgt1 and VegT)

Question 3

Which of the following are present in the Organizer?

Answer 3

Chordin, Noggin, Follistan, Xnr3

Question 4

The left side of the Xenopus embryo is determined by

Question 5

Which of the following can inhibit or block Wnt expression?

Answer 5

Cerberus, Dickkopf, Frzb, IGF, Tiki, Notum, Xwnt8

Question 6

During Mid Blastula transition in Xenopus

Question 7

The area where gray crescent forms will determine…

Question 8

The Nieuwkoop Center is

Question 9

Beta-catenin in the dorsal portion of the amphibian egg is stabilized after

Question 10

Which of the following describes organizer Functions in Xenopus

Question 11

Sox2 is expressed in the neural plates. Which of the following phenotypes would you expect to
observe after BMP inactivation in Xenopus embryos

Question 12

Which of the following molecules plays a role in controlling Wnt signaling?

Question 13

Under the influence of high levels of BMP ectoderm

Question 14

Low levels of BMP can induce

Question 15

Which of the following can inhibit BMP?

Question 16

During the formation of the head and brain in Xenopus

Question 17

The “Organizer” functions to

Question 18

In the diagram at right which adhesion protein is expressed in the area labeled

Question 19

During dorsal-ventral specification of the neural tube of vertebrates the protein that regulates
the formation and position of the floor plate is

Question 20

Which of the following belongs to the TGF-b gene family?

Question 21

Which region of the neural tube contains the least amount of sonic hedgehog?

Question 22

Frog egg microtubule are reorganized to form the Gray Crescent during the

Question 23

The amphibian Organizer is in the

Question 24

The Pitx2 molecule

Question 25

The experiment of Hemmati Brivanlou in which he tested the role of Follistatin on Activin lead to
the discovery that

Question 26

The vegetal pole in Xenopus is a source of

Question 27

Which of the following molecules have a conserved role in defining anterior posterior axis?

Question 27

Which of the following phenotypes would you expect to observe inducing Noggin expression in
a ventralized embryo

Question 28

Which of the following sentences about Xenopus Nodal Related (Xnr-1) are correct

Question 29

Ventral tube formation can be experimentally induced

Question 30

Which of the following factors can affect neural tube closure

Question 31

Genetic abnormality involving motile cilia

Question 32

During the process of garstrulation Hox genes are

Question 32

What molecule density does the diagram on the right illustrate? Choose it from the list

Question 33

Which of the following sentences is correct

Question 33

Ectopic expression of Pitx2 in the developing Xenopus can

Question 34

Spina bifida

Question 35

During the process of dorsal ventral specification of the neural tube

Question 36

Ectopic notochord can induce

Question 37

Homeotic selector genes …

Question 37

The pattern of expression of the genes that define the distinct populations of the neural tube are defined by

Question 38

Epiboly of the ectoderm in Xenopus is a process

Question 39

The Niewkoop center

Question 40

Transplant of the dorsal blastopore lip (early gastrula) to another gastrula ….

Question 41

Dorsal ventral axis in drosophila….

Question 41

Frzb

Question 42

BMP gradients define dorsal-ventral axis of developing Xenopus embryo

Question 43

Transplants of blastomers from the dorsal portion of the vegetal pole to the ventral vegetal pole
of another embryo leads to

Question 44

Noggin plays an important role in defining the

Question 45

During the definition of the anterior posterior axis in amphibians what defines the head

Question 45

Second neurulation

Question 46

Folic acid is important

Question 47

What is the doral lip and what produces the gastrulation

Answer 47

Organizer