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TLS Online TPP Program

#Question id: 12573

Which of the following conditions is the most likely indicator of a population in an extinction vortex? 

#Unit 10. Ecological Principles
  1. The population is geographically divided into smaller populations.
  2. The species is found only in small pockets of its former range
  3. The effective population size of the species falls below 500.
  4. Genetic measurements indicate a continuing loss of genetic variation.
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TLS Online TPP Program

#Question id: 15300

#Unit 5. Developmental Biology

In hippo signaling pathway, the activation of the Cdx2 gene in the trophoblast cells appears to be regulated by the Yap protein, which in turn is a cofactor for the transcription factor Tead4. Tead4 is found in the ________blastocyst
TLS Online TPP Program

#Question id: 15301

#Unit 5. Developmental Biology

Initially, the morula does not have an internal cavity. However, during a process, cavitation, the trophoblast cells secrete fluid into the morula to create a blastocoel, these 
membranes of trophoblast cells contain_______?
TLS Online TPP Program

#Question id: 15302

#Unit 5. Developmental Biology

FOXP1 is a transcription factor which stimulate the production of Oct4 and Nanog and establish pluripotency. Which of the following statements are correct regarding to the mechanism of alternative splicing of FOXP1. 
A. There are two isoforms of the FoxP1 protein, One is the product of an mRNA spliced to include a particular exon, 18b, while the other splicing variant carries exon 18a.
B. When alternative splicing generates a form including exon 18b in place of 18a, the resulting isoform (FOXP1-ES) binds to a different DNA sequence and thus controls expression of a different set of genes.
C. The protein encoded by the exon 18b– carrying mRNA is called FOXP1-ES it fails to stimulate expression of OCT4 and NANOG and instead actives genes that promote differentiation. 
D. The exon 18a– containing form encodes FOXP1 itself, and this has the opposite effect: this activates genes that promote dedifferentiation, and thus stimulates iPS cell formation.
TLS Online TPP Program

#Question id: 15391

#Unit 5. Developmental Biology

In the initiation of the vertebrate eyes, paired regions of the brain bulge out and approach the anterior region of -------germ layer:
TLS Online TPP Program

#Question id: 15392

#Unit 5. Developmental Biology

If an optic vesicle from a Xenopus laevis embryo is placed underneath head ectoderm in a different part of the head from where the frog’s optic vesicle normally occurs then what happens?
TLS Online TPP Program

#Question id: 15393

#Unit 5. Developmental Biology

First inducers (in early gastrula stages) of the lens may be: