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Why is there mRNA? | by really-joel | 2002-06-02 10:33:26 |
| Hmmm... |
by xcheopis |
2002-06-02 12:58:01 |
How complex an answer is needed?
The synthesis of all proteins begins with the interaction between ribosomes (free or bound) and mRNA. This is true for both eukaryotic and prokaryotic cells and the steps involved for both are fairly similar.
Ribosomes, which are responsible for all protein synthesis, cannot read DNA strands. Ribosomes are located in the cytoplasm, DNA is not. DNA is double-stranded, i.e., its strands are not free to interact. RNA is single-stranded, i.e., the strands are free to interact with other, complementary strands.
mRNA is located in the cytoplasm and carries a binding site for ribosomal sub-units; this binding site has its complement on the ribosome (rRNA). The binding of mRNA and ribosome initiates translation.
Some mRNA also carry targeting sequences for certain classes of proteins. These sequences are responsible for directing where the translation of the mRNA will occur. (e.g., bound or free ribosomes; RER or SER.)
So, at least two reasons why mRNA exists are:
a.) to correctly present the message to the ribosome in a legible form, and
b.) instruct the ribosome as to where the message should be translated. |
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[ Reply ] |
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mRNA is located in the cytoplasm? | by Kurioz | 2002-06-02 13:04:36 |
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Yes, it is. | by xcheopis | 2002-06-02 13:10:30 |
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Therefore | by Kurioz | 2002-06-02 15:08:30 |
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Some objections | by Beorn | 2002-06-02 14:13:31 |
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