Question

Transcription requires
A. DNA template
B. NTPs (nucleoside triphosphates)
C. RNA polymerase
D. Sigma & Rho factors

• A. A, C
• B. A, B, C, D
• C. B, C, D
• D. A, B, C

Answer 1

The correct option is B A, B, C, D

Transcription is the process of copying the genetic information from one strand of DNA (template strand) into RNA.

Requirements for a cell to undergo transcription can be understood by the following points:

i. DNA template- It is one of the two strands of DNA whose polarity is 3'→5’, it is used for transcription as RNA polymerase transcribes DNA into RNA in the 5'→3' direction only.

ii. Transcription unit- DNA template has the transcription unit with a promoter, the structural gene and a terminator.

iii. At the promoter site, initiation of transcription takes place. RNA polymerase binds to the promoter site with the help of its sigma factor that recognizes the promoter site and starts unwinding the double- stranded DNA for transcription.

iv. Once the process of transcription starts, the activated nucleoside triphosphates (NTPs) that are adenosine triphosphate (ATP), guanosine triphosphate (GTP), uridine triphosphate (UTP) and cytidine triphosphate (CTP) are brought to form a long chain of RNA. This is actually the elongation process where the structural gene is transcribed into RNA with the help of the RNA polymerase enzyme.

v. At the terminator site in the transcription unit of the template strand of DNA, RNA polymerase enzyme encounters the protein rho factor and the process of transcription gets terminated with simultaneous release of RNA.

Therefore, it can be concluded that transcription requires a DNA template strand, RNA polymerase enzyme, sigma factor, rho factor and NTPs.