#Question id: 7228
#Unit 5. Developmental Biology
Why do Drosophila wings develop in only one particular thoracic segment, legs in all three, and antennae on the head? Which of the following answer is correct?
#Question id: 7229
#Unit 5. Developmental Biology
Two embryos were injected with bicoid at early cleavage
stage. What would be the phenotypes of the resulting embryos?
#Question id: 7230
#Unit 5. Developmental Biology
Following statements are being
made regarding gradients of specific translational inhibitors in drosophila.
A. In
the anterior region, Bicoid protein prevents translation of the caudal message
by binds to a specific region of caudal’s 3′UTR. Here, bicoid recruits Bin3 (a
translation inhibitor) which prevents translation of caudal in the anterior of
the embryo.
B. In
the posterior region, Nanos protein prevents translation of the hunchback message
by forming a complex with several other ubiquitous proteins, including Pumilio
and Brat. This complex binds to the 3’UTR of the hunchback message, where it
recruits d4EHP and prevents the hunchback message from attaching to ribosomes.
C. In
the anterior region, Bicoid protein prevents translation of the caudal message
by binds to a specific region of caudal’s 5′UTR. Here, bicoid recruits pumilio
and brat (a translation inhibitor) which prevents translation of caudal in the
anterior of the embryo.
D. In
the posterior region, Nanos protein prevents translation of the hunchback message
by forming a complex with several other ubiquitous proteins, including bin3 and
smaug. This complex binds to the 3’UTR of the hunchback message, where it
recruits d4EHP and prevents the hunchback message from attaching to ribosomes.
Which of the following combination are incorrect?
#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?