The initiation of transcription requires melting of the dna double helix, i. e. separating hydrogen-bonded base pairs, immediately upstream of the +1 site. how is this melting accomplished in e. coli?
a. bases at the promoter region flip outward from the double helix into pockets on the polymerase.
b. dna helicase first unwinds the double helix around the +1 site.
c. rna polymerase gets the energy to cause separation of strands from atp hydrolysis.
d. topoisomerase first returns the linking number to lk0. dnaa: atp complexes bind to and twist the double helix at the +1 site.

What types of energy transfers and energy transportations are involved in the domino chain reaction?

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?

Question#29: why does the tropical ocean have a greater temperature range than the temperate ocean?