Which of the following does NOT protect body surfaces?

#Question id: 7257

#Unit 5. Developmental Biology

Following statements are regarding to the specification of anterior-posterior axis in drosophila.

A. The oocyte moves into the posterior region of the egg chamber, while nurse cells fill the anterior portion. The oocyte nucleus moves toward the terminal follicle cells and synthesizes Gurken protein.

B. When Gurken binds to Torpedo, the terminal follicle cells differentiate into posterior follicle cells and synthesize a molecule that activates protein kinase A in the egg.

C. Bicoid mRNA binds to dynein, a “plus-directed” motor protein associated with the nongrowing end of microtubules; dynein moves the bicoid mRNA to the anterior end of the egg.

D. Oskar mRNA becomes complexed to kinesin I, a “minus-directed” motor protein that moves it toward the growing end of the microtubules at the posterior region, where Oskar protein can bind nanos mRNA.

Which of the following is incorrect?

#Question id: 7258

#Unit 5. Developmental Biology

A four-cell embryo normally develops into a blastocyst consisting of trophectoderm (TE) cells on the outside and inner cell mass (ICM) cells inside. The transplantation experiments were done with mouse embryos.

A. If a labeled cell is placed on the outside of a very early embryo, it is likely to form extraembryonic tissues.

B. If a labeled cell is placed on the inside of a very early embryo, it is likely to form embryonic tissues.

According to above observations which of the following statement is true?

#Question id: 7259

#Unit 5. Developmental Biology

The mechanism that triggered to initiate limb bud formation involes:

A. making mesoderm instructive for limb formation

B. inducing epithelial-to-mesenchymal transitions

C. making mesoderm permissive for limb formation

D. inducing mesenchymal-to-epithelial transitions

E. specifying forelimb and hindlimb

Which of the following combinations are incorrect?

#Question id: 7260

#Unit 5. Developmental Biology

There are maternally-determined variations along the animal-vegetal axis that are necessary for normal development in sea urchin. Which of the following statements about regulation in sea urchin embryos is consistent with that fact?

#Question id: 7261

#Unit 5. Developmental Biology

The Turing model provides a framework for limb development. Following statements are regarding to this model:

A. In Turing’s model, morphogen A promotes the production of more morphogen A (autoactivation) as well as production of morphogen I. Morphogen I, however, inhibits the production of morphogen A (lateral inhibition).

B. In Turing’s model, morphogen A inhibits the production of more morphogen A (autoinhibition) as well as production of morphogen I. Morphogen I, however, promotes the production of morphogen A (lateral activation).

C. In Turing’s model, the reaction-diffusion dynamics can tell us how the limb bud acquires its proximal- distal polarity as well as how the number of digits is regulated at the distal tip of the limb.

D. The reaction-diffusion system has been proposed to be sufficient for establishing patterns of precartilage and noncartilage tissues.

E. According to this model, along the proximal-distal axis the AER dividing into two domains 1-the inhibitory domain 2-the active domain.

F. According to this model, along the proximal-distal axis the AER dividing into three domains 1-the inhibitory domain 2-the active domain 3-frozen domain.

Which of the following combinations are incorrect?

#Question id: 7262

#Unit 5. Developmental Biology

Match the following Gene (column I) with their function (column II).

Which of the following is correct?