why doesn't mRNA last forever in a cell?
479736
This is more of an issue in eukaryotes where there is a lag time between DNA transcriptino and mRNA translation.  One reason that mRNA doesn't hang around in the cell is that it serves no purpose for the cell...mRNA is pretty much useless until it is translated.  Also, mRNA that is about to be translated is modified with a 5' cap and a 3' poly-A tail.  If the mRNA doesn't get to the ribosome (and therefore doesn't undergo these modifications) it is highly susceptible to 5'-3' exonucleases and some endonucleases (depending on the organism).
207487
No.  Transcription makes mRNA.  DNA is made by the process of replication.
472444
Listen carefully and ignor anyone who tells you diffrently. All the informaton needed for every protien in the body is stored as DNA. When a particular protien is needed, the streatch of DNA that codes for it is copied into RNA. THis piece of RNA is called a transcript. \n\nThe transcript is usually proccessed in the cell before being sent to the ribosom. There the ribosom reads the nucleic acids in groups of three. So no one nucleic acid makes a protien, but three nucleic acids determine one amino acid. A string of amino acids makes up a protien.
448144
Neither is true.  In a broad sense #1 is true, but every time a cell divides errors accumulate.  So every cell has a unique signature, but it may only be one base pair difference in 3 billion.  #2 is not true either, error accumulation leads to diseases like cancer (mostly cancer).  Aging is thought to occur by telomere shortening. Every time a cell replicates, the telomere shortens.  It can be repaired by telomerase, but in some cases telomerase is not active.  When it gets too short the chromosome can stick to another chromosome, leading to aneuplody.  Once the telomere gets short, the cell enters crisis.  Two things can happen; one is that the cell dies.  Two is that the cell becomes immortalized, which is the next step on the road to cancer.\n\nPS DNA damage does not cause AIDS!
222501
nothing does last forever
72936
Technically, a virus is just a single strand of RNA in a protein shell. If you can get it hot enough to denature the protein, it should "die," though I don't believe it is technically "alive." Viruses work by using your living cells to replicate themselves. They can't do it on their own. When you catch a cold, your cells become little virus factories, churning out millions of replicas of the virus that can then get into other living cells and infect them. That's how viruses spread, multiply, and mutate within living organisms. Fire probably destroys just about any virus, but I'm not going to say that with 100% certainty. Hope that helps a little.
409458
Here is the first paragraph of a review article answering your question, see the source below...\n\nLike the discovery of splicing three decades ago, the unearthing of RNA interference (RNAi) and microRNAs (miRNAs) once again has everyone’s attention focused on posttranscriptional phenomena. During RNAi, dsRNA formed in cells by DNA- or RNA-dependent synthesis is processed to ∼20 bp small interfering RNAs (siRNAs) containing 2 nt (nucleotide) 3′ overhangs. These siRNAs are then incorporated into an R NA-i nduced s ilencing c omplex (RISC), which mediates the degradation of mRNAs with high sequence complementarity to the siRNA. MiRNAs are ∼21 nt regulatory RNAs excised from genome-encoded precursors folding into dsRNA-like hairpins. With few exceptions, animal miRNAs base pair imperfectly to the 3′-untranslated region of target mRNAs and inhibit protein accumulation by an unknown mechanism, while plant miRNAs show nearly precise complementarity to their targets and trigger mRNA degradation. This miRNA dualism and observations that miRNAs can act under some circumstances as siRNAs, and vice versa, highlight similarities between the siRNA and miRNA pathways. Indeed, maturation of both RNA classes involves Dicer proteins, and, like siRNAs, miRNAs function as RNP particles, miRNPs or miRISCs, whose composition and, probably, assembly are related to those of the RISC (Sontheimer [2005]; Tomari and Zamore [2005] [ Sontheimer, 2005, Tomari and Zamore, 2005]; consult these reviews when discussed findings are not specifically referenced).
435654
DNA has the original code (for proteins) and RNA is the copy(of DNA) that leaves from the nucleus. Because DNA can't leave the nucleus so RNA copies the "code" from DNA.
892517
RNA is significantly less stable than DNA.  Both in terms of overall structural integrity, and its succeptability to mutation.\n\nThere is a rather large gain of fitness by having DNA storage of information instead of RNA.  After a few billion years that's why we are where we are.\n\nA few things (RNA viruses) continue to utilize RNA as their genetic material, but their success is due to the very lack of stability that makes an RNA-based genetic system a bad idea for "living" organisms.
214091
Transcription is when the nucleus of a cell wants to send a "message" for a protein (polypeptide chain) to be made. It copies this "message" from part of the DNA onto an m(essenger)RNA strand, in which the Thymine of the DNA is now the Uracil of the RNA.\n\nex) DNA message: TAC CGG TAA\n           mRNA: AUG GCC AUU\n\nAfter that is translation, where the message from mRNA gets read by the ribosome to build a polypeptide chain that will eventually become a protein!
856076
DNA is a double helix while mRNA is a single stranded molecule.
774548
i gave u a website on ur previous answer that can answer ur question of RNa\nand the seqence is called TRNA   fits in the protein of ribosome
930674
I cant really write a story!\nThe cell membrane and lysozymes guard the cell from the things which cause harm.  The DNA in the nucleus determines what type of cell it is could be equivelent to religion or rules in society.  RNA transcribe from DNA and make 1000's of proreins which do 10000's of different thing in the cell.  This is a bit like a production line in a factory.  The proteins are made in steps using different types of RNA.  The proteins go through postage and packaging in the endoplasmic reticulum.  This is a bit like a post office because they get marked for postage for different regions in the cell.  The mitochondria would have to be the powerstations!\nThe cell cytoskeletion is like the motorway and roads.  \n\nThe DNA could also be thought of as a library and the RNA thought of as the students.\n\nCant think of anything else!
651143
In translation, the ribosomes attach to the mRNA to create or synthesize polypeptides or proteins.  The ribosome attaches to a signal recognition particle (srp) which attaches to the ER at the translocation complex. This is your binding site. The srp then leaves and the polypeptide continues growing through the translocation complex into the ER until the process is complete. The ribosome then detaches releasing the mRNA. \n\nHope this helps. -r
821772
There are a number of ways to kill some viruses in eukaryotic cells but usually there are other smarter viruses not affected in the same mechanism.  I will only give a couple of interesting examples.  The first is based on the cellular RNA interference (RNAi) mechanism.  Double strand RNA viruses are processed by an RNase III enzyme into ~20 base pair (bp) long short RNA.  These can bind to mRNA of the virus and lead to their degradation via the RNAi process with Ago2 and the so called RNA induced silencing complex (RISC) mediated pathway.  Some viruses are smart enough to produce a small inhibitor molecule that binds the 20 bp small RNA and thus inhibit the RNAi process.\n\nThere are other processes that target long double stranded RNA - most like from viruses because the cell does not make this type of RNA duplexes.  The recognition of the long dsRNA activate the interferon pathway and lead to apoptosis of the cell and hopefully killing the viruses with it.  However, again there are viruses that produce molecules that inhibit apoptosis and thus will survive long enough to replicate themselves before the cells eventually die.
803356
As you know, mRNA has copied the protein-making instructions from the DNA. Well, tRNA brings the required amino acids to build the primary structure of the protein, as is stated by the instructions on the mRNA.
478310
As far as using for detection, its very vulnerable to showing false positives from non-specific binding.  In addition, because of the relatively low level of mRNA, it can only be used for fairly abundant messages.  It is somewhat difficult to separate non-specific from specific binding, but of course it can be done.  In addition, it only shows the presence of message-it does not tell about the level of protein translation.