The diagram, shown in attatched image, shows an mRNA that is alternatively spliced. The alternatively spliced variant contains Exon 1, Exon 2, and Exon 4. Indicate below if a splice site is used, blocked by a modifying protein such that the spliceosome must choose a different site, or skipped to make this alternatively spliced

Identify the correct recognition site for ribosomal subunit binding during translation. the 30s subunit binds to the 7-methylguanosine cap at the 3’ end of eukaryotic mRNA the 60s subunit binds to the “Shine-Dalgarno” sequence at the 5’ end of eubacterial mRNA the 40s subunit binds to the 7-methylguanosine cap at the 5’ end of eukaryotic mRNA the 70s subunit binds to the “Shine-Dalgarno” sequence at the 5’ end of eukaryotic mRNA the 50s subunit binds to the 7-methylguanosine cap at the 3’ end of eubacterial mRNA

List three types of alternative splicing patterns and how they lead to the production of different protein isoforms.

There are a number of conserved sequences found in an mRNA that dictate where splicing occurs. Where are these sequences found relative to the exon-intron junctions? What is the significance of these sequences in the splicing process? One of these important regions is the branch point A found in the intron. What is the role of the branch point A in the splicing process, and can this be accomplished with the OH group on either the 2′ or the 3′ carbon?

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…

Although the genetic code is universal, a few organisms such as Paramecium have a slightly modified version in which UGA, a stop codon for most organisms, codes for tryptophan in Paramecium. Suppose that the researcher wanted to make an in vitro translation system using all of the components from Paramecium. Which of the components, if any, would she need to replace in order to have an in vitro system that was universal? Possible Answers: A. She would need to leave out the P site. B. She would need to leave out the termination factor proteins. C. She would need to leave out the tRNA that recognizes UGA. D. She would need to leave out the ubiquitin