In drosophila, the somatic cells of the hub are able to regulate stem cell proliferation by secreting the paracrine factor Unpaired onto the cells attached to them. Unpaired activates the JAK-STAT pathway in the adjacent germ stem cells to specify their self-renewal. Those cells that are distant from the paracrine factor cannot receive this signal, they begin their differentiation into the sperm cell lineage. This means hub cells act as

#Question id: 7263

#Unit 5. Developmental Biology

Following statements are regarding to the drosophila.

 A. At the completion of oogenesis, the bicoid message is anchored at the anterior end of the oocyte and the nanos message is tethered to the posterior end in translationally dormant condition.

 B. The translation inhibitors Smaug and CUP. Smaug binds to the 3’UTR of both bicoid and nanos mRNA and recruits the CUP protein that prevents the association of the message with the ribosome as well as recruiting other proteins that deadenylate the message and target it for degradation.

 C. The bicoid-Exuperantia complex is transported out of the nurse cells and into the oocyte via microtubules (Kinesin ATPase).

 D. Two other maternally provided mRNAs—caudal and hunchback are critical for patterning the anterior and posterior regions of the body plan, respectively.

 Which of the following combination is correct?

#Question id: 7262

#Unit 5. Developmental Biology

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

Which of the following is correct?

#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: 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: 5522

#Unit 5. Developmental Biology

In reptiles, birds, and mammals, mesoderm is made by invagination and involution into the

#Question id: 5523

#Unit 5. Developmental Biology

Ectodermal cells condense into placodes that change into