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TLS Online TPP Program

#Question id: 7250

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?

#Unit 5. Developmental Biology
  1. A and B
  2. B, C and D
  3. A, B and C
  4. C and D
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TLS Online TPP Program

#Question id: 11916

#Unit 10. Ecological Principles

Which one of the following  features of an later community?
TLS Online TPP Program

#Question id: 11266

#Unit 10. Ecological Principles

Which of the following options lists ecosystems in increasing order of consumption efficiency of herbivore?
TLS Online TPP Program

#Question id: 3815

#Unit 3. Fundamental Processes

Use the figure to answer the following question. A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life-form that has DNA. You grow the cells in 15N medium for several generations and then transfer them to 14N medium. Which pattern in the figure would you expect if the DNA was replicated in a conservative manner?
TLS Online TPP Program

#Question id: 10423

#Unit 6. System Physiology – Plant

Which of the following responses include processes such as the promotion of lettuce seed germination, inhibition of hypocotyl elongation, and regulation of leaf movements?
TLS Online TPP Program

#Question id: 33510

#Unit 2. Cellular Organization

Myoclonic epilepsy with ragged-red fiber disease (MERRF) is caused by a mutation in the mitochondrial gene called as