5) The UB food service hands you two organisms they found contaminating the drin

Question

5) The UB food service hands you two organisms they found contaminating the drinks, and both organisms were isolated from both milk (lactose containing) and juice (glucose containing) substances, and thus can grow in both substances. We call these organisms S (Starbucks) and C (CVS), based on where they were identified. You want to identify differences in transcription between the two organisms. You isolate the TOTAL RNA, and run the RNA for both S and C organisms on a gel You identify two large bands on the RNA gel, with many small bands in between. These RNA pperto bundant and very large fiom a mas point of view. Based on the lectures, these RNA that form these large, prominent bands, are most likely which type of RNA in the cell? Why? To further study transcriptional differences, in the S and C organisms, you add the antibiotic Rifampin, which inhibits transcription. You isolate TOTAL RNA and you measure the concentration of RNA B) What is the simplest way to measure nucleic acid (RNA) concentration? How would you measure the change in RNA concentration? C) Do you expect the RNA to increase, decrease, or remain the same? Explain. You want to compare transcription in the two organisms, S and C. You fractionate the RNA from both organisms, and you find that the S organism contains mRNA, whereas the C organism contains RNA, but not mRNA. D) What chemical features distinguish mRNA from other types of RNA? Does mRNA exist in both prokaryotes and eukaroytes? Explain.

Explanation / Answer

A.The large RNAs are ribosomal RNAs. rRNAs are the major chunk of RNAs in a cell and constitutes 80-90% of total RNA.

B.The simplest way to measure RNA concentration is by reading the RNA at wavelength 260nm on a spectrophotometer. The change in the RNA concentration can be estimated by comparing the concentration before and after the treatment.

C.We expect the levels of RNA would decrease due to the degradation of RNA. The half-life of single-stranded RNA is very less. Due to the treatment with Rifampin, the transcription would be blocked thus, no new RNA would form.

D.The mRNA contains the genes and carries the information that is translated into proteins. The eukaryotes have intron sequences interspersed between exons, the coding part. The introns are spliced out in eukaryotes to form mature mRNA. The prokaryotes lack introns.

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