#Question id: 7231
#Unit 5. Developmental Biology
Kragl and colleagues (2009) performed an experiment in which they transplanted limb tissue from a salamander whose cells expressed green fluorescent protein (GFP) into different regions of limbs of normal salamanders that did not have the GFP transgene. If they transplanted the GFP-expressing limb cartilage into a salamander limb that did not contain the GFP transgene, the GFP-expressing cartilage would integrate normally into the limb skeleton. They later amputated the limb through the region containing GFP-marked cartilage cells. The blastema was found to contain GFP-expressing cells, and when the blastema differentiated, the only GFP-expressing cells found were in the limb cartilage. Similarly, GFP-marked muscle cells gave rise only to muscle, and GFP-marked epidermal cells only produced the epidermis of the regenerated limb. Which of the following phenomenon is proved according to experiment?
#Question id: 7232
#Unit 5. Developmental Biology
During early development in sea urchin following events
occur.
A.
localized maternal factors in egg
B.
organizer specified in vegetal region (micromeres)
C.
induction of endomesoderm
D.
b-catenin accumulation
E.
animal–vegetal axis
which of the following sequence of developmental event is correct?
#Question id: 7233
#Unit 5. Developmental Biology
Following statements are regarding to the coordination of Dictyostelium discoideum stalk and spore maturation by cAMP.
A. In prestalk cells at the slug tip, cAMP is synthesized by ACR and can either be hydrolysed by RegA or bind to PKA to trigger stalk encapsulation, which normally occurs when the tip projects upward at the onset of fruiting body formation and loses ammonia (NH3) by gaseous diffusion.
B. NH3 inhibits PKA by indirectly activating cAMP hydrolysis via DhkC-RdeA mediated phosphorylation of RegA.
C. In prespore cells, PKA activation occurs as a consequence of a signalling cascade that is activated by SDF-3, which inhibits the synthesis of GABA by prespore cells.
D. Secreted GABA then acts on prestalk cells to induce the cell-surface exposure of the serine protease domain of the ABC transporter TagC.
E. GABA also acts on prespore cells to induce secretion of AcbA, which in turn is cleaved by the TagC protease to produce the peptide SDF-2.
F. SDF-2 next activates the histidine phosphatase activity of DhkA, causing activation of cAMP hydrolysis by RegA. This allows cAMP to accumulate and activate PKA, which in turn induces spore encapsulation.
Which of the following combinations are correct?
#Question id: 7234
#Unit 5. Developmental Biology
Studies from the sea urchin developmental biology, Eric Davidson’s group envisions a network involving cis regulatory elements (such as promoters and enhancers) in a logic circuit connected to one another by transcription factors. Following statements are given regarding to this network.
A. The network receives its first inputs from transcription factors in the egg cytoplasm.
B. The network self-assembles from the ability of the maternal transcription factors to recognize cis-regulatory elements of particular genes that encode other transcription factors.
C. The new set of transcription factors activate autocrine signaling pathways that activate specific transcription factors in neighboring cells.
D. This network of interconnections among genes that specify cell types known as a gene regulatory network (GRN).
Which of the following statements are correct?
#Question id: 7235
#Unit 5. Developmental Biology
Following statements are regarding to the wingless gene in drosophila.
A.
In the cells transcribing the wingless gene, wingless mRNA is translocated by
its 3’UTR to the apex of the cell. At the apex, the wingless message is translated
and secreted from the cell.
B.
The cells expressing engrailed can bind this protein because they contain
Patched, which is the Drosophila membrane receptor protein for Wingless.
C.
Binding of Wingless to Frizzled activates the hedgehog signal transduction
pathway, resulting in the continued expression of engrailed.
D.
Wingless protein also acts in an autocrine fashion, maintaining its own
expression.
Which of the following combinations is correct?
#Question id: 7236
#Unit 5. Developmental Biology
Which of the following statement justified that the PMZ in chick is
functionally equivalent to the amphibian Nieuwkoop center?
A.
The posterior marginal zone produces Wnt8c and that, the PMZ cells secrete Vg1,
a member of the TGF-β family.
B.
PMZ cells capable of inducing the accumulation of β-catenin
C.
PMZ cells secretes BMP, a member of the TGF-β family.
D.
PMZ secretes its own Nodal antagonist—the Lefty protein.
Which of the following combination is correct?