Which of the following is true concerning the first nucleotide incorporated into an RNA chain?
A) The first nucleotide incorporated into the RNA chain retains its 5'-triphosphate
B) The first nucleotide is always GMP
C) The first nucleotide is always cleaved off post-transcriptionally
D) The first nucleotide is always modified after transcription

Question

Quizplus · Accepted Answer

The first nucleotide incorporated into an RNA chain retains its 5'-triphosphate group, which distinguishes it from subsequent nucleotides that are added in a 5' to 3' direction, each losing two of their phosphates as a pyrophosphate. This feature is crucial for the initiation of RNA synthesis and is not seen in DNA synthesis, where the initiating nucleotide only retains a single phosphate.

Which of the Following Is True Concerning the First Nucleotide