Consider following statements for catalytic mechanism of RNA polymerase

A. RNA synthesis by RNA polymerase. The reaction involves two Mg2+ ions, coordinated to the phosphate groups of the incoming nucleoside triphosphates (NTPs)

B. Three Asp residues, which are highly conserved in the RNA polymerases of all species. One Mg2+ ion facilitates attack by the 39-hydroxyl group on the phosphate of the NTP; the other Mg2+ ion facilitates displacement of the pyrophosphate, and both metal ions stabilize the pentacovalent transition state.

C. About 17 bp of DNA are unwound at any given time. RNA polymerase and the transcription bubble move from left to right along the DNA as shown, facilitating RNA synthesis. Movement of an RNA polymerase along DNA tends to create negative supercoils (overwound DNA) ahead of the transcription bubble and positive supercoils (underwound DNA) behind it.

D. The RNA polymerase is in close contact with the DNA ahead of the transcription bubble as well as with the separated DNA strands and the RNA within and immediately behind the bubble. A channel in the protein funnels new NTPs to the polymerase active site. The polymerase footprint encompasses about 35 bp of DNA during elongation.

#Question id: 7283

#Unit 5. Developmental Biology

The Drosophila orthodenticle gene and the vertebrate Otx genes are homologous and provide a good example of the conservation of gene function during evolution. Which of the following statement is correct regarding to the expression of gene expression.

#Question id: 7284

#Unit 5. Developmental Biology

Choose the correct match.

#Question id: 7285

#Unit 5. Developmental Biology

During xenopus gastrulation, C3a functions as a short-range chemoattractant to guide the radial intercalation movements of cells. If Knockdown of C3a with antisense morpholinos results:

#Question id: 7286

#Unit 5. Developmental Biology

Which of the floral whorls is affected in apetala 3/pistillata (ap3/pi) mutants?

#Question id: 7287

#Unit 5. Developmental Biology

Following statements are regarding to the the floral quartet model and the underlying ABCDE model of organ identity determination in Arabidopsis thaliana.

A. Five floral organ identities (sepals, petals, stamens, carpels, and ovules) are specified by the formation of floral organ-specific tetrameric complexes of MADS-domain transcription factors that bind to two nearby enhancer elements, forming a DNA loop in between.

B. A complex of two class A proteins (APETALA 1) and two class E proteins  (SEPALLATA) determines petal identity.

C. A complex of one class A protein, one class E protein, and one of each of the class B proteins (APETALA 3 and PISTILLATA) determines sepal identity.

D. A complex of one class E protein, two class B proteins, and one class C protein (AGAMOUS) determines stamen identity, while a complex of two class E proteins and two class C proteins determines carpel identity.D. A complex of one class E protein, two class B proteins, and one class C protein (AGAMOUS) determines stamen identity, while a complex of two class E proteins and two class C proteins determines carpel identity.

E. A complex of one class E protein, one class C protein, and one of each of the class D proteins (SHATTERPROOF and SEEDSTICK) controls ovule identity.

Which of the following combination are correct?

#Question id: 7288

#Unit 5. Developmental Biology

Following statements are regarding to the expression of genes in floral quartate model in Arabidopsis thaliana.

A. Sepals- AP1(heterodimer) + SEP(homodimer)

B. Petals-AP1(monomer)+PI(monomer)+AP3(monomer)+SEP(monomer)

C. Stamens- AP3(monomer)+PI(monomer)+AG(monomer)+SEP(monomer)

D. Carpels- AG(homodimer)+SEP(homodimer)

Which of the following genetic combinations are incorrect?