Question

Use this representation to answer the following question.

DNA template strand 5' ________ 3'
DNA nontemplate strand 3' ________ 5'
Given the locally unwound double strand above, in which direction does the RNA polymerase move while transcribing DNA?
A)
`5' \rightarrow 3'` along the double-stranded DNA B)
`3' \rightarrow 5'` along the template strand C)
`5' \rightarrow 3'` along the template strand D)
`5' \rightarrow 3'` along the complementary strand E)
`3' \rightarrow 5'` along the complementary strand move

Answer 1

B) 3' - 5' direction along the template strand

Step-by-step explanation:

Transcription is the first stage of gene expression or protein synthesis. It involves making a complementary strand of mRNA from a DNA template. The process of transcription is carried out by an enzyme called RNA polymerase. RNA polymerase initially binds to a specific region on the DNA called PROMOTER region. This triggers the initiation process.

The RNA polymerase then begins to read one strand of the DNA molecule called TEMPLATE strand. The template strand reads in the 3'-5' direction. The RNA polymerase, unwinding the double helix of the DNA as it progresses, reads the nucleotide bases on the template DNA strand and synthesizes complementary bases on the growing RNA molecule. The RNA transcript contains same information as the non-template DNA strand with the exception of Uracil base instead of Thymine. The RNA strand reads in the 5'-3' direction.

Hence, the RNA polymerase moves in the 3'-5' direction on the template strand during transcription.

Answer 2

DNA template strand 3' ________ 5'

DNA nontemplate strand 5' ________ 3'

Option B

Step-by-step explanation:

DNA template strand is also the coding strand from which the mRNA is transcribed thus to transcribe an mRNA moving in the 5' to 3' direction, the template strand must run in the 3' to 5' direction while the non template which is the non coding strand and also is the same as the mRNA strand runs in the 5' to 3' direction.

The RNA polymerase moves and transcribes this mRNA in the 3' to 5' direction along the template strand.