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: 7082

#Unit 5. Developmental Biology

In chick embryo, at the anterior end of the primitive streak is a regional thickening of cells called:

#Question id: 3400

#Unit 11. Evolution and Behavior

Which of the following influence effective population size?

a. Sex ratio

b. variation between individuals in reproductive success

c. Fluctuations in population size

d. Small breeding group

#Question id: 28818

#Unit 2. Cellular Organization

Which of the following condition is involve to unfolds the myosin II, active and can assemble into bipolar filaments for contraction?

#Question id: 5292

#Unit 8. Inheritance Biology

A transformation experiment is performed with a donor strain that is resistant to four drugs: W, X, Y, and Z. The recipient is sensitive to all four drugs. The treated recipient population is divided up and plated on media containing various combinations of the drugs. The table below shows the results:

Following observation are given

A) X gene is obviously quite distant from the other three genes

B) Y gene is obviously quite distant from the other three genes

C) The Order is three closely link gene W Z Y

D) The Order is three closely link gene W X Z

Which of the following combination is correct?

#Question id: 10273

#Unit 6. System Physiology – Plant

The existence of different pathways that serve a similar function and can replace each other without a clear loss in function is called,