Question

The list of events below describes the processing of ribosomal RNAs. Please select the choice that lists the events in correct sequential order.

1.Methyl groups are added to specific bases and the 2′-carbon atom of some ribose sugars
2.Transcription of the rRNA precursors from DNA
3.Cleavage of precursor rRNA
4.ndividual rRNA molecules ready for ribosome assembly
5.Trimming of precursor rRNA
a) 2, 1, 3, 5, 4
b) 2, 3, 5, 1, 4
c) 2, 1, 5, 3, 4
d) 2, 5, 1, 3, 4
e) 2, 3, 1, 5, 4

Answer 1

The correct sequence for the processing of ribosomal RNAs is: transcription of rRNA precursors from DNA, addition of methyl groups to specific bases and ribose sugars, trimming of precursor rRNA, cleavage of precursor rRNA, and the final preparation of individual rRNA molecules for ribosome assembly; the correct option is (c) 2, 1, 5, 3, 4.

Step-by-step explanation:

The processing of ribosomal RNAs (rRNAs) within a eukaryotic cell follows a precise sequence of transcriptional and post-transcriptional modifications. The correct sequential order of these events is as follows:

1. Transcription of the rRNA precursors from DNA.
2. Methyl groups are added to specific bases and the 2′-carbon atom of some ribose sugars.
3. Trimming of precursor rRNA.
4. Cleavage of precursor rRNA.
5. Individual rRNA molecules ready for ribosome assembly.

Therefore, the correct option that lists the events in their proper order is (c) 2, 1, 5, 3, 4.