#Question id: 7269
#Unit 5. Developmental Biology
Following statements are regarding to gastrulation in chick embryo.
A.
During gastrulation, future mesodermal and endodermal cells migrate from the
epiblast through the primitive streak into the interior of the blastoderm.
B.
An aggregation of cells, known as Hensen’s node, forms at the posterior end of
the streak.
C.
As the streak extends, cells of the epiblast move toward the primitive streak,
through it, and then outward again underneath the surface to give rise
internally to the mesoderm and endoderm, the latter displacing a lower layer of
cells called the endoblast.
D.
Cells that remain in the epiblast form the endoderm.
Which of the following statements are correct?
#Question id: 567
#Unit 1. Molecules and their Interaction Relevant to Biology
Penicillin and related drugs inhibit the enzyme; this enzyme is produced by
#Question id: 7250
#Unit 5. Developmental Biology
Following
statements are regarding to signals that regulate axis extension in chick
embryos.
A.
In the stage 10 chick embryo, Fgf8 inhibits expression of the retinoic acid
(RA) synthesizing enzyme Raldh2 in the presomitic mesoderm and the expression
of the RA receptor RARβ in the neural ectoderm, thus preventing RA from
triggering differentiation in the caudal-lateral epiblast cells and the
caudal-most paraxial mesoderm.
B.
Fgf8 inhibits Sonic hedgehog (Shh) expression in the neural tube floorplate,
controlling the onset of ventral patterning genes.
C.
FGF signaling is also required for expression of Delta1 in the medial portion
of the caudal-lateral epiblast cells and promotes expression of Wnt8c.
D.
Fgf8 decays in the caudal paraxial mesoderm, Wnt signaling, most likely
provided by Wnt8c, now acts to promote Raldh2 in the adjacent paraxial mesoderm.
RA produced by Raldh2 activity expresses Fgf8 and Wnt8c.
Which of the following statements are correct?
#Question id: 10720
#Unit 10. Ecological Principles
What is the Jaccard index between the two communities?
#Question id: 10409
#Unit 6. System Physiology – Plant