Question

Double-stranded DNA molecule is being transcribed, only part of which is shown below. If the molecule is translated from left to right, one of the nucleotides shown in bold would be the first transcribed in this small molecule. 5'-ATGATCGGATCGATCCAT-3' 3'-TACTAGCCTAGCTAGGTA-5' Which of the following is the correct mRNA produced from the transcription of this DNA molecule?

a. -3'-UACUAGCCUAGCUAGGUA-5'

b. -5'-UACUAGCCUAGCUAGGUA-3'

c. -3'-AUGAUCGGAUCGAUCCAU-5'

d. -5'-AUGAUCGGAUCGAUCCAU-3'

Answer 1

The correct mRNA produced from the transcription of the DNA sequence 5'-ATGATCGGATCGATCCAT-3' should be 5'-AUGAUCGGAUCGAUCCAU-3', which aligns with option d.

Step-by-step explanation:

The question relates to the process of transcription where a single stranded RNA is synthesized from a DNA template. To determine which mRNA is produced during this process, we must identify the correct base pairing between the DNA template and the mRNA. In RNA, adenine (A) pairs with uracil (U) and cytosine (C) pairs with guanine (G).

Given the DNA sequence 5'-ATGATCGGATCGATCCAT-3', the correct mRNA should be the complement of this sequence but with uracil (U) replacing thymine (T). Hence, the correct mRNA sequence should be read in the 5' to 3' direction as 5'-AUGAUCGGAUCGAUCCAU-3', matching with option d.

The bold nucleotides indicate the start of transcription, and since transcription proceeds in the opposite direction of the annotation (from 3' to 5' on the template), it confirms that the bold A in the 5'-end of the given DNA would be the first to be transcribed into mRNA.

Answer 2

d. -5'-AUGAUCGGAUCGAUCCAU-3'

Step-by-step explanation:

Transcription is the first step of gene expression. It is a process in which mRNA is produced from the DNA which acts as a template. Enzyme involved in transcription is RNA polymerase. Only one strand of DNA is used as a template and it is the one with 3'-5' direction. So, this means that the synthesized mRNA has the 5'-3' direction. This is because RNA polymerase has the ability to add nucleotides only to 3' end.

Transcription is a highly regulated process, performed in the nucleus of the cell (in eukaryotes).