Question

Which of the following steps in transcription is catalysed by RNA polymerase?

• A. All of the above
• B. Termination
• C. Elongation
• D. Initiation

Answer 1

Answer: (C)

.

Types involved in transcription:

1) Initiation

• It marks the beginning of transcription, when the enzyme RNA polymerase binds to a region of a gene called the promoter.
• This signals the DNA to unwind and the enzyme will make mRNA strand with a complementary sequence of bases.

2) Elongation

• Elongation is the addition of nucleotides to the mRNA strand. RNA polymerase reads the unwound DNA strand and builds the mRNA molecule, using complementary base pairs.
• During this process, an adenine (A) in the DNA binds to an uracil (U) in the RNA.

3) Termination

• Termination marks the end of transcription when RNA polymerase encounters a stop sequence in the gene.
• The mRNA strand is complete, and it detaches from DNA.