Question

Which of the following are true about transciption. (more than one may apply)

Select one or more:

a. Synthesis of the RNA will go in the 5' to 3' direction

b. The template strand will go in the 3' to 5' direction

c. The coding strand will go in the 3' to 5' direction

d. The growing RNA strand will be antiparallel with the DNA template.

e. The growing RNA strand will be parallel with the DNA template.

Answer 1

Ans. Transcription is the process of synthesis of RNA from DNA. RNA are always synthesized in 5' to 3' direction on template / noncoding strand of DNA by RNA polymerase enzyme. Thus the polarity of template strand on which RNA is synthesized will be 3'to 5' since the synthesized RNA is antiparallel and complementary to the template strand.

The second strand of the double stranded DNA other then the template strand is called as non-template or coding strand which is similar in sequence to synthesized RNA except U in RNA in place of T in DNA. The polarity of the coding strand is 5'to 3'direction and it's parallel to RNA.

Hence, option (c), stating that coding strand have 3'to 5'polarity, is false and other all options including options (a), (b), (d), and (e) are true for transcription.