Based on your knowledge of introns and pre-mRNA splicing, discuss whether or not you think alternative splicing fully explains the existence of introns. Can you think of other possible reasons to explain their existence?

Explain why DNA replication must be primed by RNA.   Explain how splicing happens in 4-5 sentences. Splicing is caused by a complex called spliceosome. This complex removes introns and joins the exons. It is called post transcriptional processing of RNA. (What I have so far) If you can only answer the first question, that is fine! Thank you for your help!

A common feature of many eukaryotic mRNAs is the presence of a rather long 3′ UTR, which often contains consensus sequences. Creatine kinase B (CK-B) is an important enzyme in cellular metabolism. Certain cells—termed U937D cells—have lots of CK-B mRNA, but no CK-B enzyme is present. In these cells, the 5′ end of the CK-B mRNA is bound to ribosomes, but the mRNA is apparently not translated. Something inhibits the translation of the CK-B mRNA in these cells. Researchers introduced numerous short segments of RNA containing only 3′ UTR sequences into U937D cells. As a result, the U937D cells began to synthesize the CK-B enzyme, but the total amount of CK-B mRNA did not increase. The introduction of short segments of other RNA sequences did not stimulate the synthesis of CK-B; only the 3′ UTR sequences turned on the translation of the enzyme. On the basis of these results, propose a mechanism for the inhibition of CK-B translation in the U937D cells. Explain how the introduction of short…

Define both transcription and translation. In addition, describe the role(s) of each of the following in the processes of gene expression and protein synthesis:  DNA, mRNA, tRNA, rRNA, ribosome(s), RNA polymerase, codon, anticodon, amino acid(s) and polypeptide(s). Be detailed in your answer.