Question

RNA polymerase moves along the template strand of DNA in the ________ direction, and adds nucleotides to the ________ end of the growing transcript.

a.3' to 5'; 5'
b.3' to 5'; 3'
c.5' to 3'; 5'
d.5' to 3'; 3'

Answer 1

RNA polymerase moves along the DNA template strand in the 3' to 5' direction and adds nucleotides to the 3' end of the RNA, so the correct answer is d. 5' to 3'; 3'. This mechanism ensures the RNA strand is synthesized in the 5' to 3' direction.

Step-by-step explanation:

RNA polymerase moves along the template strand of DNA in the 3' to 5' direction, and adds nucleotides to the 3' end of the growing transcript. Thus, the correct answer is: a. 3' to 5'; 5' b. 3' to 5'; 3' c. 5' to 3'; 5' d. 5' to 3'; 3'.The RNA polymerase binds to the DNA at a sequence called a promoter during the initiation of transcription. As elongation proceeds, the DNA is continuously unwound ahead of the enzyme and rewound behind it.

In the process of transcription, the RNA polymerase enzyme binds to the DNA at a specific region known as the promoter. The enzyme then reads the DNA template strand in a 3' to 5' direction. This reading direction is necessary because RNA polymerase can only add RNA nucleotides to the 3' end of the emerging RNA strand, thereby synthesizing the RNA in a 5' to 3' direction. It's important to note that while RNA polymerase conducts this process in transcription, DNA polymerase performs a similar function during DNA replication.