#Question id: 7226
#Unit 5. Developmental Biology
Experimental
evidences suggest that control of proximal-distal specification of the limb is
correlated with the age of the progress zone mesenchyme. Match the following
experiment (Column I) with their results (Column II).
|
Column I |
Column II |
|
A.
when an early wing bud progress zone was transplanted to a late wing bud |
I.
Normal limbs form |
|
B.
when a late wing-bud progress zone was transplanted to an early wing bud |
II.
Lack of intermediate structures |
|
C.
when an early wing bud progress zone was transplanted to an early wing bud |
III.
An extra set of ulna and radius formed |
|
D.
when a late wing-bud progress zone was transplanted to a late wing bud |
|
#Question id: 7227
#Unit 5. Developmental Biology
The regulative ability of the
limb bud has recently been highlighted by a remarkable experiment of nature. In
numerous ponds in the United States, multilegged frogs and salamanders have
been found. The presence of these extra appendages has been linked to the
infestation of the larval abdomen by parasitic trematode worms. The eggs of
these worms apparently split the developing tadpole limb buds in several
places, and the limb bud fragments develop as multiple limbs. This shows:
A. The
limb field represents a harmonious equipotent system.
B. The
limb field do not represents harmonious equipotential system because different
types of genes express during proximal to distal growth.
C. The
limb field represents coupled system wherein one gene maintain the expression
of other genes.
D. The
limb field represents a harmonious equipotent system because only Hox genes
expresses all along the limb axis.
E. The
limb field represents cells of the limb region can be instructed to form any
part of the limb.
Which of the following statements are correct?
#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?