#Question id: 7187
#Unit 5. Developmental Biology
Following statements regarding to feedback loops during limb development.
A. When the limb bud is relatively small, an initial positive feedback loop is established between Fgf10 produced in the mesoderm and Fgf8 produced in the ectoderm, promoting limb outgrowth.
B. As the limb bud grows, the ZPA is established, and another regulatory loop is created by inhibiting the BMP in mesoderm and maintain FGF expression.
C. In anterior region of the limb bud, Fgf8 positively regulates Etv4/5, which in turn repress Shh in this region, further reinforcing the posterior-to-anterior gradient of Shh from the ZPA.
D. In posterior region of the limb bud, Fgf8 positively regulates Etv4/5, which in turn repress Shh in this region, further reinforcing the posterior-to-anterior gradient of Shh from the ZPA.
Which of the following combinations are incorrect?
#Question id: 7188
#Unit 5. Developmental Biology
when RNAi completely eliminates beta-catenin from non-regenerating flatworms then which of the following results are obtained?
#Question id: 7189
#Unit 5. Developmental Biology
Following statements were made regarding vulval development in C. elegans:
A. The formation of the anchor cell is mediated by lin-12, the C. elegans homologue of the Notch gene.
B. The formation of the anchor cell is mediated by lin-12, the C. elegans homologue of the Delta gene.
C. The lin-12 gene needs to function only in that cell destined to become the uterine precursor cell.
D. Presumptive Anchor cell also need lin-12.
E. Two cells originally synthesize both the signal for uterine differentiation (the LAG-2 protein, homologous to Delta) and the receptor for this molecule (the LIN-12 protein, homologous to Notch.
Which one of the following options represents a combination of correct statements?
#Question id: 7190
#Unit 5. Developmental Biology
In
amphibia, few mutants (Column A) and their affected event or organ (Column B).
|
Column A |
Column B |
|
I.
mRNA of cadherin is destroyed by antisense oligonucleotides |
a.
Epiboly |
|
II.
Loss of methylation on H3K4 |
b.
Convergent extension |
|
III.
Loss of function of tbxt gene |
c.
Blastocoel |
|
IV.
Knockdown of C3a with antisense morpholinos |
d.
MBT |
|
V.
Inhibition of PCP pathway |
e.
Notochord |
Which of the following is correct?
#Question id: 7191
#Unit 5. Developmental Biology
In tunicate embryo, Presumptive endoderm originates from the vegetal A4.1 and B4.1 blastomeres. The specification of these cells coincides with the localization of β-catenin. Which of the following statement is incorrect?
#Question id: 7192
#Unit 5. Developmental Biology
The following are statements regarding the development and maintenance of anterior and posterior compartments in each segment of Drosophila. Which of the following is correct?