#Question id: 7251
#Unit 5. Developmental Biology
Following statements are regarding to the three “toggle switches” activated
along the anterior-posterior axis to establish gap gene domains in drosophila.
A.
The mutual inhibition of Knirps and Hunchback positions the Knirps protein
domain at around 60–80% along the anterior-posterior axis.
B.
Hunchback inhibits Krüppel expression at high concentrations but promotes it at
intermediate concentrations.
C.
Hunchback inhibits Krüppel expression at intermediate concentrations but
promotes it at high concentrations.
D.
Krüppel and Giant mutually inhibit each other’s synthesis.
E.
Kruppel inhibits Giant expression at high concentrations but promotes it at
intermediate concentrations.
Which of the following statements are correct?
#Question id: 7252
#Unit 5. Developmental Biology
Although some species differences exist, the process of primary neurulation is relatively similar in all vertebrates. Primary neurulation can be divided into four distinct but spatially and temporally overlapping stages:
A. Bending of the neural plate
B. Closure of the neural tubeC. Elongation and folding of the neural plate
D. Convergence of the neural folds
C. Elongation and folding of the neural plate
D. Convergence of the neural folds
What is the correct sequence?
#Question id: 7253
#Unit 5. Developmental Biology
In drosophila, the segment polarity genes encode proteins that are constituents of the Wnt and Hedgehog signaling pathways. Which of the following is correct regarding to model for transcription of the segment polarity genes engrailed (en) and wingless (wg).
#Question id: 7254
#Unit 5. Developmental Biology
Following statements regarding to the micromeres specification and regulatory input in sea urchin embryo. Which of the following statement is correct?
#Question id: 7255
#Unit 5. Developmental Biology
The
hypostome acted as an “organizer” of the hydra. This notion has been confirmed
by:
A.
when transplanted, the hypostome can induce host tissue to form a second body
axis.
B.
the hypostome do not produces the head inhibition signal.
C.
the hypostome is the only “self-differentiating” region of the hydra.
D.
the hypostome produces a “head activation signal” that suppresses the formation
of new organizing centers.
Which one of the following combinations are incorrect?
#Question id: 7256
#Unit 5. Developmental Biology
Sox9 is an autosomal gene involved in several developmental processes, most notably bone formation. In the gonadal rudiments, Sox9 induces testis formation. Expression of the Sox9 gene is specifically upregulated by the combined expression of Sry and Sf1 proteins in Sertoli cell precursors. Thus, Sry may act merely as a “switch” operating during a very short time to activate Sox9, and the Sox9 protein may initiate the conserved evolutionary pathway to testis formation. Following statements are regarding to the functions of Sox9.
A. It appears to be able to activate its own promoter, thereby allowing it to be transcribed for long periods of time.
B. It activates the ability of β-catenin to induce ovary formation, either directly or indirectly.
C. It binds to cis-regulatory regions of numerous genes necessary for testis production.
D. Sox9 binds to the promoter site on the gene for anti-Müllerian hormone, providing a critical link in the pathway toward a male phenotype.
E. Sox9 inhibits the expression of the gene encoding Fgf9, a paracrine factor.
Which of the following statements are correct?