2006-07-21 08:43:05 · 4 answers · asked by shortstuff2 1 in Science & Mathematics ➔ Biology
DNA is not faithfully translated into proteins. U must be aware that the m-RNA is modified and spliced, such that the final m-RNA has only the exons that are needed for making proteins. All the introns (non-coding) sequences of the m-RNA (copied from the DNA) are removed as they are not essential. This process is carried out without any change to the DNA sequence. But if DNA were to be directly translated into proteins, we would have to contend with either modified DNA or non-functional proteins.
Moreover, the percentage of error in protein translation is lesser with an m-RNA intermediate, because DNA damages are rectified during the process of transcription of m-RNA, in a repair process signalled by a stalled RNA polymerase.
2006-07-21 22:26:21 · answer #1 · answered by Anonymous · 0⤊ 1⤋
Tons of reasons. Here are some...
Having extra steps allows more types of regulation at different levels.
It is also an amplification step. Let's assume that a certain type of molecules can generate a different type at a maximum rate of 10 molecules per minute. If you had DNA->protein then you would have maximum 10 protein molecules per min.
When you have DNA->RNA->protein you can have 100 (1 DNA->10 RNA->10*10 protein)
The mRNA can localize at different parts of the cell creating patterns within the cell.
DNA can be safely stored in the nucleus (in eukaryotes) and parts that don't need to be transcribed can be safely packed together.
Also in order to make DNA accessible to the ribosomes you would need to keep it unwound and single stranded for a very long time and that would take up too much energy (and space)
RNA can be processed in different ways so that from the same sequence you can get more than one proteins
The list goes on...
2006-07-21 15:57:01 · answer #2 · answered by bellerophon 6 · 0⤊ 0⤋
Simply put, DNA is like that book that you can't check out of the reference section of the library. It provides the basic information or blueprint and is reserved as a MASTER copy to keep the information safe from wear or damage. Or if you perfer, imagine you wrote a book. You'd keep one pristine copy at home--safe. You'd use another for your publisher to make changes to or to edit--a working copy. RNA is your working copy.
2006-07-21 15:47:40 · answer #3 · answered by tigerzntalons 4 · 0⤊ 0⤋
Now that you asked the whole question I can give you the answer. ASK YOUR SCIENCE TEACHER!!!
2006-07-21 15:47:45 · answer #4 · answered by Anonymous · 0⤊ 0⤋