In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a  single species dominated the field. A possible factor in this secondary succession was

#Question id: 7211

#Unit 5. Developmental Biology

Choose the correct match.

#Question id: 7212

#Unit 5. Developmental Biology

The regeneration blastema forms from pluripotent stem cells called clonogenic neoblast. If cNeoblasts are essential for regeneration, their total loss should prevent regeneration. Following statements are made in respect to planaria regeneration are given below.

(A) The gene sigma/zeta is expressed by all neoblasts and has become the most common marker for their identification across planarian species.

(B)   In planaria, Wnt/β-catenin functions to establish dorsal ventral polarity of the regenerating flatworm.

(C)   Inhibition of Wnt/β-catenin signaling in regeneration-deficient species yields fully functional regenerated heads.

(D)   If β-catenin is eliminated from the posterior (tail-forming) blastema by RNA interference, that blastema will form a tail.

Which of the above statements are true?

#Question id: 7213

#Unit 5. Developmental Biology

Following statements are regarding to the early development of C.elegans (expression of PIE-1):

A. Segregation of PIE-1 determinant into the P1 blastomere at the 2-cell stage

B. The sperm centrosome activates the presence of the PAR-3/PAR-6 complex in the posterior of the egg

C. PIE-1 is degraded in the resulting anterior AB cell, it is preserved in the posterior P1 cell

D. PIE-1 is degraded in the resulting posterior P1 cell, it is preserved in the anterior AB cell

Which of the following combination is incorrect?

#Question id: 7214

#Unit 5. Developmental Biology

The anterior posterior compartment of each segment of drosophila is defined by wingless and engrailed genes. The following statements are given towards explaining their regulation:

A.cells secreting Hedgehog protein activate wingless expression in their neighbors, and the Wingless protein signal, which is received by the cells that secreted Hedgehog, serves to maintain hedgehog (hh) expression.

B.Engrailed protein also acts in an autocrine fashion, maintaining its own expression.

C.The cells expressing engrailed can bind wingless protein because they contain Frizzled, which is the Drosophila membrane receptor protein for Wingless.

D.Binding of Wingless to Frizzled activates the hedgehog signal transduction pathway, resulting in the continued expression of engrailed.

Which of the following option has all the incorrect statements?

#Question id: 7215

#Unit 5. Developmental Biology

Limb bud initiation could have either initiation factors genomes Listed below are some limb bud initiation (Column A), their lateral plate mesoderm (Column B).

#Question id: 7216

#Unit 5. Developmental Biology

Following statements are about Specification of cell fate by the Dorsal protein. Which of the following statement is correct?