Question

Direction of RNA synthesis and direction of reading of the template DNA strand is
(a)5’- 3’ and 3’-5’
(b)3’- 5’ and 5’-3’
(c)5’-3’ and 5’-3’
(d)3’-5’ and 3’-5’

Answer 1

Hint: The process of mRNA synthesis using DNA coding strand as the template is known as Transcription and it occurs in the nucleus. RNA polymerase always added complementary nucleotides to the 3’ end of the RNA strand.

Complete answer:
Direction of RNA synthesis and direction of reading of the template DNA strand is 5’- 3’ and 3’-5’. The transcription unit has three regions in DNA and they are a promoter, the structural gene, and terminator and there are three stages: initiation, elongation, and termination.
Initiation- RNA polymerase binds to the promoter which is found near the beginning of a gene. Also the DNA opens up in the promoter region so that RNA polymerase can begin transcription. Each gene has its promoter and after bonding RNA polymerase separates the DNA strands this helps provide the single-stranded template.
Elongation- One strand of DNA (template strand) acts as a template and as RNA polymerase reads this template the polymerase builds an RNA molecule out of complementary nucleotides, making a chain that grows from 5' to 3'. RNA polymerase moves forward along the template strand which is in the 3' to 5' direction, opening the DNA double helix as it goes. The RNA binds for a short while; the DNA closes back up and forms a double helix. The RNA transcript carries similar information as the DNA (coding strand) but is present with uracil (U) instead of thymine (T).
Termination- Terminators signal that the RNA transcription is complete. They tell the transcript to be released from the RNA polymerase.
So, the correct answer is 5’- 3’ and 3’-5’.

Note: A sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product (either RNA or protein) is known as a gene. A gene is a physical and functional unit of heredity and is made up of DNA.