#Question id: 3533
#Unit 8. Inheritance Biology
What would be the frequency of dominant phenotype for all character individuals from a mating of two AaBbCc individuals?
#Question id: 2654
#Unit 2. Cellular Organization
Regulation of the lac operon can be envisioned as regulation of enzyme synthesis by its
#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: 14853
#Unit 13. Methods in Biology
#Question id: 4069
#Unit 3. Fundamental Processes
Which of the following can be identified using a series of promoter linker scanning mutations?
a. areas of the promoter that are non-essential
b. areas of the promoter that are essential
c. the presence of separate transcriptional control regions
d. spacing constraints on separate transcriptional control regions