#Question id: 12642
#Unit 6. System Physiology – Plant
#Question id: 5205
#Unit 11. Evolution and Behavior
Why is it preferable to use large computers and databases in searching for individual genes, rather than testing each sequence for possible function?
#Question id: 4104
#Unit 3. Fundamental Processes
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: 801
#Unit 1. Molecules and their Interaction Relevant to Biology
Identify the type of DNA from the structures given below and match the correct form with its characteristics described.
#Question id: 10346
#Unit 6. System Physiology – Plant
Nitrite reductase will convert nitrite to ammonium. There are two types of nitrite reductase characteristics given below;
a) Both nitrite reductase consist of a single 63kD polypeptide
b) In leaf chloroplasts and root plastids contain different forms of the nitrite reductase enzyme
c) In shoot nitrite reductase directly dependent on the light reaction by the ferredoxin, it activates nitrite reductase in choloroplast
d) NADPH in the roots is provided by pentose phosphate pathway, it also activate nitrite reductase in the plastids
Which of the correct statement about nitrite reductase characteristics?