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TLS Online TPP Program

#Question id: 4806

Four incompletely link gene as cis configuration, Heterozygote ABCD/abcd produced a gamete with genotype AbCD is due to

#Unit 8. Inheritance Biology

  1. Single cross over between A and B gene

  2. Double cross over, one is A & B, second is C & D

  3. Double cross over, one is A & B, second is B & C

  4. Single cross over between B and C gene

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TLS Online TPP Program

#Question id: 7245

#Unit 5. Developmental Biology

Gradients of Wnt are essential for normal regeneration of a head and a tail by planaria. Which one of the following statement is incorrect?
TLS Online TPP Program

#Question id: 7246

#Unit 5. Developmental Biology

Treatment of Xenopus embryos with lithium dorsalizes the embryos by interfering with cell-cell signaling pathways. What, if anything, is the effect of lithium on hydra, and what might we infer about its mechanism of action?
TLS Online TPP Program

#Question id: 7247

#Unit 5. Developmental Biology

Which statement correctly characterizes regeneration in the mammalian nervous system?
TLS Online TPP Program

#Question id: 7248

#Unit 5. Developmental Biology

Planning of the Xenopus mesoderm along the dorso-ventral axis contains an antagonistic relationship between chordin and bmp-4. Is there an analogy here to dorso-ventral patterning in the Drosophila embryo?
TLS Online TPP Program

#Question id: 7249

#Unit 5. Developmental Biology

Match the following proteins (column I) in nematodes with their functions (column II).

Column I

Column II

A. SKN-1

i. specify the Anterior-Posterior axis

B. TBX-35

ii. specify MS fates

C. MOM-2 and MOM-5

iii. controls the fate of the EMS blastomere

D. PHA-4

iv. activates mesodermal genes in the MS cell

Which of the following is correct?
TLS Online TPP Program

#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 RARĪ² 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?