Following statements were made about the post-transcriptional processing of rna in eukaryotes. soon after transcription initiation, rna polymerase li pauses-30

Krishan k jakhad

3. B, D and E are correct I think. Large introns in relation to alternative splicing and gene evolution. Splice sites are the critical elements at the end of introns and are extremely diverse, as thousands of different sequences act as bona fide in the human transcriptome. Most are recognized by base-pairing with the end of the U1 small nuclear RNA (snRNA). so B statement is valid.\n\nTransesterification is a catalytic reaction that converts lipids into fatty ester methyl esters and glycerol as coproduct through four steps. Nuclear pre-messenger RNA (pre-mRNA) splicing is an essential processing step for the production of mature mRNAs from most eukaryotic genes. Splicing is catalyzed by a large ribonucleoprotein complex, the spliceosome, which is composed of five small nuclear RNAs and more than 100 protein factors. Despite the complexity of the spliceosome, the chemistry of the splicing reaction is simple, consisting of two consecutive transesterification reactions. The presence of introns in spliceosomal RNAs of certain fungi has suggested that splicing may be reversible; however, By using affinity-purified spliceosomes, we have shown that both catalytic steps of splicing can be efficiently reversed under appropriate conditions. These results provide considerable insight into the catalytic flexibility of the spliceosome.