#Question id: 7194
#Unit 5. Developmental Biology
Formation
of digits and sculpting the tetrapod limb requires death of specific cells in
the limb in a programmed manner. Which one of the following interactions could
explain proper limb formation?
#Question id: 7195
#Unit 5. Developmental Biology
Given below are some of the statements regarding toll signalling pathway in drosophila.
A. Dorsal protein is a transcription factor with homology to the Rel/nuclear factor kappa B (NFκB) family of vertebrate transcription factors, which are involved in regulation of gene expression in vertebrate immune responses.
B. Toll signalling pathway is also used in the adult fly in defense against infection.
C. In the Drosophila embryonic Toll pathway Dorsal is held inactive in the nucleus by the protein Cactus.
D. The ligand for Toll is a fragment of the protein Easter, which is generated in the ventral vitelline space by the protease Spatzle.
E. When Toll is activated by binding the Spätzle fragment, its cytoplasmic domain binds a complex of the adaptor proteins dMyD88 and Tube. Tube interacts with, and activates, the protein kinase Pelle.
F. Activation of Pelle leads to the dephosphorylation of Cactus. This releases Dorsal, which is then free to enter a nucleus.
Choose the most appropriate combination of correct statements:
#Question id: 7196
#Unit 5. Developmental Biology
Under the process of endochondral ossification-
#Question id: 7197
#Unit 5. Developmental Biology
Following statements are regarding to PAR proteins and the establishment of polarity during early development in nematodes.
A. The internal cytoplasm contains PAR-3, PAR-6, and PKC-3, and the cortical cytoplasm contains PAR-2 and PAR-1.
B. PAR-3 and PAR-6, interacting with the protein kinase PKC-3 are uniformly distributed in the cortical cytoplasm. PKC-3 restricts PAR-1 and PAR-2 to the internal cytoplasm by phosphorylating them.
C. Once PAR-1 is in the cortical cytoplasm, it phosphorylates PAR-3, causing PAR-3 (and its binding partner, PKC-3) to leave the cortex.
D. During first cleavage, the metaphase plate is closer to the posterior, and the fertilized egg is divided into two cells, one having the anterior PARs (PAR-1 and PAR-2) and one having the posterior PARs (PAR-3 and PAR-6).
Which of the following statements are correct?
#Question id: 7198
#Unit 5. Developmental Biology
Which
of following graphs correctly represents ectoderm biased to become neural ectoderm
in xenopus.
#Question id: 7199
#Unit 5. Developmental Biology
Following statements are regarding to the establishment of ventral axis in Drosophila.
A. Ventral follicle cells synthesize Pipe. Pipe signal sulfates ventral vitelline proteins.
B. GD cleaves Snake to its active form and forms a complex with Snake and uncleaved Easter proteins.
C. Sulfated vitelline membrane proteins bind Gastrulation-defective (GD).
D. Easter protein is cleaved into its active form. Cleaved Easter binds to and cleaves Spätzle; activated Spätzle binds to Toll receptor protein.
E. Dorsal protein enters the nucleus and ventralizes the cell.
F. Toll activation activates Tube and Pelle, which phosphorylate the Cactus protein. Cactus is degraded, releasing it from Dorsal.
Which of the following is the correct sequence?