Why is RNA necessary to act as a messenger?
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In principle there is no reason why DNA could not act as a messenger. The enzymology of producing a mDNA is really not any different than the enzymology of DNA replication. The vast majority of the information content in a messenger resides in the sequences of bases, which are essentially the same for DNA and RNA, and not in secondary or tertiary structure, which does tend to differ.
The most likely answer is history. The currently most plausible account of early life is the RNA World hypothesis[1] [2] [3] . Although the origins of the RNA World itself are uncertain and highly debated, there is a broad consensus that RNA predated DNA as a genetic material: RNA was both the genome and the messenger. DNA eventually displaced RNA as the genome (except in RNA viruses, which still persist). It could do this by being redundant - there was probably a stage in which both DNA and RNA genomes existed in cells.
But a cell would have a much harder time evolving to use DNA as a messenger. In particular, ribosomes would have to adapt to accept the different molecular geometry of DNA vs RNA. Ribosomes are high-performance machines, finely tuned to achieve very high rates of protein synthesis while retaining remarkably high levels of accuracy. Even a few percent reduction in performance, needed to accommodate DNA messengers, would consign a cell to evolutionary death.
So the answer, almost certainly, is history - it is too hard to get to DNA from RNA in the case of messengers.
hope this helps.................
hey don't forget to hit this answer as the brainliest..................
thanks.
The most likely answer is history. The currently most plausible account of early life is the RNA World hypothesis[1] [2] [3] . Although the origins of the RNA World itself are uncertain and highly debated, there is a broad consensus that RNA predated DNA as a genetic material: RNA was both the genome and the messenger. DNA eventually displaced RNA as the genome (except in RNA viruses, which still persist). It could do this by being redundant - there was probably a stage in which both DNA and RNA genomes existed in cells.
But a cell would have a much harder time evolving to use DNA as a messenger. In particular, ribosomes would have to adapt to accept the different molecular geometry of DNA vs RNA. Ribosomes are high-performance machines, finely tuned to achieve very high rates of protein synthesis while retaining remarkably high levels of accuracy. Even a few percent reduction in performance, needed to accommodate DNA messengers, would consign a cell to evolutionary death.
So the answer, almost certainly, is history - it is too hard to get to DNA from RNA in the case of messengers.
hope this helps.................
hey don't forget to hit this answer as the brainliest..................
thanks.
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Messenger RNA (mRNA) is a large family of RNA molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression.
Messenger RNA is a Workorder with Blueprints sent from the Main office (nucleus) to the Factory (ribosome).
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