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: 539

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following mutases catalyze the formation of a 2,3-BPG intermediate?

A) muscle phosphoglycerate mutases

B) plant phosphoglycerate mutases

C) yeast phosphoglycerate mutases

#Question id: 540

#Unit 1. Molecules and their Interaction Relevant to Biology

During strenuous exercise, the NADH formed in the glyceraldehyde 3-phosphate dehydrogenase reaction in skeletal muscle must be reoxidized to NAD+ if glycolysis is to continue.  The most important reaction involved in the reoxidation of NADH is:

#Question id: 541

#Unit 1. Molecules and their Interaction Relevant to Biology

The overall △G for glycolysis is -72 kJ/mol in erythrocytes. Which statement below is true?

A) The value of △G0ʹ is also -72 kJ/mol since the cytosol pH is close to 7.

B) The free energy of glycolysis is found as the sum of the standard free energy changes for

the individual pathway reactions.

C) The negative sign of △G shows that this pathway will proceed toward product (pyruvate) under normal cellular conditions.

#Question id: 542

#Unit 1. Molecules and their Interaction Relevant to Biology

Hamsters love to run on exercise wheels. Prolonged running at a high rate of speed requires ATP. Could a hamster with a defective gene for the enzyme lactate dehydrogenase meet the extra ATP demand for prolonged, fast wheel-running by maintaining a high rate of glycolysis? Why or why not?

#Question id: 543

#Unit 1. Molecules and their Interaction Relevant to Biology

If glucose labeled with 14C at C^-1 (the aldehyde carbon) were metabolized in the liver, the first radioactive pyruvate formed would be labeled in:

#Question id: 544

#Unit 1. Molecules and their Interaction Relevant to Biology

One of the enzymes involved in glycolysis, aldolase, requires Zn2+ for catalysis. Under conditions of zinc deficiency, when the enzyme may lack zinc, it would be referred to as the: