#Question id: 7217
#Unit 5. Developmental Biology
Following statements regarding to the metamorphic changes of frog development.
A. The metamorphic changes are brought about by the secretion of the hormone thyroxine (T4) into the blood by the thyroid gland
B. the conversion of T4 into the more active hormone tri-iodothyronine (T3) by the target tissues
C. the degradation of T3 in the target tissues
D. by the deiodinases enzymes T3 converted into T4 in target tissues.
Which of the following options are correct?
#Question id: 7218
#Unit 5. Developmental Biology
Following statements are regarding to convergent extension of the dorsal mesoderm in xenopus.
A. For convergent extension the first force is a polarized cell cohesion wherein the involuted mesodermal cells intercalate and the second force is differential cell cohesion.
B. The intercalations of mesodermal cells, both mediolaterally and radially, are stabilized by the planar cell polarity (PCP) pathway that is initiated by Wnts independent of β-catenin signaling.
C. The intercalations of mesodermal cells, are stabilized by the planar cell polarity (PCP) pathway that is initiated by Wnts dependent of β-catenin signaling.
D. Another factor regulating convergent extension is calcium influx from environment.
E. Ca2+ is released from intracellular stores and is required for convergent extension.
Which of the following combination is correct?
#Question id: 7219
#Unit 5. Developmental Biology
Following statements are regarding to the role of the Disheveled and β-catenin proteins in specifying the cells of the sea urchin embryo.
A. During normal development, β-catenin accumulates predominantly in the micromeres and somewhat less in the veg2 tier cells.
B. In embryos treated with lithium chloride, β-catenin accumulates in the nuclei of all blastula cells and the cells of the animal pole become specified as ectoderm.
C. When β-catenin is prevented from entering the nuclei (i.e., it remains in the cytoplasm), the vegetal cell fates are not specified, and the entire embryo develops as a ciliated ectodermal ball.
D. When β-catenin is prevented from entering the nuclei (i.e., it remains in the cytoplasm), the vegetal cell fates are specified, and the entire embryo specified as endoderm and mesoderm .
Which of the following statements are true?
#Question id: 7220
#Unit 5. Developmental Biology
The anterior-posterior polarity of the drosophila embryo is established while the oocyte is still in the egg chamber, and it involves interactions between the developing egg cell and the follicular cells that enclose it. Following are certain statements:
A. The gurken message appears to be synthesized in the oocyte, and it is transported into the nurse cells. Here it becomes localized between the nucleus of nurse cells and the cell membrane, and it is translated into Gurken protein.
B. Gurken signal is received by the follicle cells at that position through a receptor protein encoded by the torpedo gene.
C. This signal results in the “posterior -anteriorization” of these follicle cells.
D. Posterior follicle cells signals to recruit Par-1 protein organizes microtubules specifically with their minus (cap) and plus (growing) ends at the anterior and posterior ends of the oocyte, respectively.
E. The motor protein kinesin, is an ATPase that will use the energy of ATP to transport material to the plus end of the microtubule. Dynein, however, is a “minus-directed” motor protein that transports its cargo in opposite direction.
F. These zygotic messengers bicoid and nanos mRNAs are carried by motor proteins along the microtubules to the anterior and posterior ends of the oocyte, respectively.
Which combination of the above statements are correct?
#Question id: 7221
#Unit 5. Developmental Biology
The cells of the neural plate are characterized by expression of the Sox family of transcription factors (Sox1, 2, and 3). These factors-
#Question id: 7222
#Unit 5. Developmental Biology
During development of sea urchin, The fates of the different cell layers are determined by which process?