Question

Question: How many adenylate residues are added at the 3' end during the processing of hnRNA in eukaryotes?
A. 50-100
B. 100-150
C. 600-700
D. 200-300

Answer 1

Hint: Heterogeneous nuclear RNA is referred to as hnRNA. It alludes to the substantial pre-mRNAs of different nucleotide sequences produced by RNA Polymerase II and transformed into cytoplasmic mRNAs in the nucleus. RNA Capping, Transcription using RNA Polymerase II.
Complete step-by-step solution:
Longer and confined in the nucleus, the primordial mRNA transcript is also known as pre-mRNA or heterogeneous nuclear RNA (hnRNA). hnRNA has a cap (7-methyl guanosine triphosphate, or 7 mG) at the 5’ end and a tail of poly A (Adenylate residues of 200 to 300) at the 3’ end.

These procedures are referred to as capping and tailing, respectively. The cap is an altered guanosine triphosphate molecule (GTP).
Non-coding introns and coding exons are the two sorts of segments that make up the main mRNAs.
Through a procedure known as RNA splicing, the introns are eliminated, and the exons are then connected in a predetermined order.
The addition of stabilizing and signalling components to the 5′ and 3′ ends of the molecule, as well as the deletion of the introns, are the three most crucial processes in pre-mRNA processing.
The mRNA transcript can occasionally be "edited" after it has been transcribed.
Hence, option D is correct.
200 - 300 adenylate residues are added at 3' end during the processing of hnRNA in eukaryotes.
Note: In an organism, RNA serves a variety of purposes, including coding, decoding, regulating, and the expression of genes. RNA makes up around 5% of the weight of a human cell. DNA only makes up a little portion of a cell—about 1%. Human cells contain RNA in both the cytoplasm and nucleus.