Question

1a. Explain how bacteria can have poly cistronic mRNAs. 1b. Explain why eukaryotes don't have poly cistronic mRNAs. 2. Draw all the parts of a typical sliced out mRNA lariat, showing the donor (gu) and acceptor (ag) nucleotides, and the conserved branch point A. Indicate any unusual base pair linkages and explain where and what they are (arrows and a few words!). 3. Give the levels of B-galactosidase activity (+ or -) expected for the following partial diploids for the lac operon. Lactose absent Lactose present I+P+ O-Z-/I+P-O+Z+ IS P+O+Z-/I-P+O+Z+ I-P+ OC Z-/I-P+O+Z+ I+P+ OC Z+/IS PO+Z+

Answer 1

determine the start (a). The way that bacteria codon differs from the method used in eukaryotes. Bacterial mRNAs do not have s' caps, so dubosomal assembly by definition must be different. When an mRNA codes for multiple polypeptides, the MONA is said to be polycistront. Prokaryotes utilize polyushonic mRNA sia oferoms. The bacterial genome, being very efficient contains feature known as operons. An operon us a contiguous stretch of DNA that codes for more than one polypeptide, che tromscript of which will be contained in a single mRNA. In d. coli, che lae operon codes for a single mRNA, but that mRNA encodes & protum. Each of the protum, coding segments has its own translational Staet site and stop odon Polycistrance is the formation of mature MANA from premature mRNA would have been more complex and difficult process. Zukaryotes hame greater gene diversity them the prokaryoles. 80 eukaryotes hame evolved to have monocistronic genes.