Question

What happens during the initiation step of DNA transcription? A ribosome attaches to the initiation codon of a completed mRNA strand. RNA polymerase moves along the template strand of the DNA creating an mRNA strand. A portion of the DNA unwinds and RNA polymerase attaches to the DNA within the transcription bubble. The mRNA detaches from the RNA polymerase as the RNA polymerase leaves the DNA strand.

Answer 1

Answer:

A portion of the DNA unwinds and RNA polymerase attaches to the DNA within the transcription bubble.

Explanation:

Transcription is the process in which DNA template is used to synthesize  mRNA.

There are three steps of transcription:

• Initiation

It is the process in  which a portion of DNA unwinds and RNA polymerase binds to the promotor region on the DNA.

• Elongation

It is the process in which RNA polymerase moves along the DNA template and synthesizes mRNA. During this process, unwinding of double stranded DNA takes place.

• Termination

As the RNA polymerase moves along the DNA template, it finally reaches a termination signal and then stops synthesizing. It is followed by the detachment of the newly formed mRNA and RNA polymerase from the DNA.

QUESTION:

• A ribosome attaches to the initiation codon of a completed mRNA strand.

This is the incorrect answer choice as this process does not happen in the process of transcription. This event happens in the process of translation in which mRNA is used to synthesize proteins or amino acids. mRNA attaches to ribosome during this process.

• RNA polymerase moves along the template strand of the DNA creating an mRNA strand.

This is the incorrect answer choice as this event takes place in the process of elongation.

• A portion of the DNA unwinds and RNA polymerase attaches to the DNA within the transcription bubble.

This is the correct answer choice as this event takes place in the process of initiation of transcription

• The mRNA detaches from the RNA polymerase as the RNA polymerase leaves the DNA strand.

This is the incorrect answer choice. This event takes place in the event of termination of transcription.