#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?
#Question id: 7200
#Unit 5. Developmental Biology
Following statements are regarding to Reaction-diffusion mechanism for proximal-distal limb specification. Which of the following statement is incorrect?
#Question id: 7201
#Unit 5. Developmental Biology
Many of the cell and tissue movements in Xenopus
gastrulation happen simultaneously. Still identify the different types of
behaviors that occur during Xenopus gastrulation:
A. Epiboly: The thinning
and spreading of the animal cap cells over the vegetal hemisphere, powered by
proliferation and radial intercalation.
B. Vegetal rotation:
Vegetal cells asymmetrically press up against the inner blastocoel roof on the
dorsal side.
C. Bottle cell formation
and invagination: The leading edge of invaginating cells crawls up onto the
blastocoel roof.
D. Involution and cell
migration: Localized apical constriction at the dorsal blastopore lip creates
anisotropic forces that foster invagination.
E. Convergence and
extension: The targeted medial-to-lateral intercalation of cells on the midline
(convergence) drives anterior-posterior axis elongation (extension).
Which of the following definition are correct according to their process?
#Question id: 7202
#Unit 5. Developmental Biology
Identify
the correct match of the modes of regeneration (column I) with their definition
(column II)
|
Column I |
Column II |
|
A. Stem
cell-mediated regeneration |
i. Through
the re-patterning of existing tissues. There is often little new growth but
rather cell death and a change in cell type (i.e., transdifferentiation into
a different cell fate). This results in a rescaling of the whole organism as
well as regeneration of the missing part. |
|
B. Epimorphosis |
ii. The
differentiated cells divide but maintain their differentiated functions. The
new cells do not come from stem cells, nor do they come from the
dedifferentiation of adult cells. |
|
C. Morphallaxis |
iii. Adult
structures can undergo dedifferentiation to form a relatively
undifferentiated mass of cells (a blastema) that then redifferentiates during
morphogenesis of the new structure. |
|
D. Compensatory
regeneration |
iv. Stem
cells allow an organism to regrow certain organs or tissues that have been
lost. |