#Question id: 7164
#Unit 5. Developmental Biology
If an amphibian zygote is manipulated so that the first cleavage plane fails to divide the gray crescent, then ________.
#Question id: 7165
#Unit 5. Developmental Biology
Embryonic induction, the influence of one group of cells on another group of cells, plays a critical role in embryonic development. In 1924, Hans Spemann and Hilde Mangold transplanted a piece of tissue that influences the formation of the notochord and neural tube, from the dorsal lip of an amphibian embryo to the ventral side of another amphibian embryo. If embryonic induction occurred, which of the following observations justifies the claim of embryonic induction?
#Question id: 7166
#Unit 5. Developmental Biology
Just prior to the onset of gastrulation in an embryo, the "organizer" cells are specified. If you were to experimentally block the specification of these cells, what would you expect the result to be in the developing embryo?
#Question id: 7167
#Unit 5. Developmental Biology
The following
experiment is designed to study the role of several hormones in the regulation
of metamorphosis in frogs.
Group # |
Treatment |
Days
to Metamorphosis |
1 |
Saline |
30 |
2 |
Prolactin |
> 100 |
3 |
TSH |
15 |
4 |
Thyroxine |
10 |
5 |
Corticosterone |
30 |
6 |
Thyroxine
+ Corticosterone |
5 |
7 |
Prolactin + TSH |
30 |
8 |
Thyroid gland
removed |
> 100 |
These results suggest which of the following about prolactin (group 2 and group 7) at the dose tested?
#Question id: 7168
#Unit 5. Developmental Biology
Which one of the following
signaling pathways will best support the mediolateral intercalation in the
formation of the primitive streak in chick?
#Question id: 7169
#Unit 5. Developmental Biology
Before oogenesis begins, the oogonium divides four times with incomplete cytokinesis, giving rise to 16 interconnected cells in drosophila. These 16 germline cells, along with a surrounding epithelial layer of somatic follicle cells, constitute the egg chamber in which the oocyte will develop. These germline cells include: