"(1)What are the transcriptional products of RNA polymerase-3?
(2)Difference between ""capping"" and ""tailing"".
(3)Expand hnRNA."
class 12th CBSE Biology sample paper
Answers
(1)The RNA polymerase III is responsible for transcription of tRNA, 5srRNA, and snRNAs (small nuclear RNAs).
The genes transcribed by RNA Pol III fall in the category of housekeeping genes whose expression is required in all cell types and most environmental conditions
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(2). In capping an unusual nucleotide (methyl guanosine triphosphate) is added to the 5'-end of hnRNA.
In tailing, adenylate residues (200-300) are added at 3'-end in a template independent manner. It is the fully processed hnRNA, now called mRNA, that is transported out of the nucleus for translation.
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(3) Heterogeneous nuclear RNA (hnRNA).
It is defined as the Precursor mRNA (pre-mRNA), also termed heterogeneous nuclear RNA (hnRNA), is an immature single strand of messenger ribonucleic acid (mRNA). pre-mRNA is synthesized from a DNA template in the cell nucleus by transcription.