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.

The correct answer is B. DNA helicase first unwinds the double helix around the +1 site.

Explanation:

The helicase is an enzyme that specifically breaks the hydrogen bonds of the bases in the transcription process. As E. Coli is a prokaryote, then, the transcription only occurs in one point of the circular DNA. The promoter region indicates where the DNA polymerase has to start replicating and the Topoisomerase unwinds the parts of the DNA that are being excessively twisted because of the separation of the two strands.

sea breeze

explanation:

cool air is going towards land allowing for the land to be cooler, the hotter air gets pushed away from the land.

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.