DNA Transcription
When writing a letter, you select from 26 different letters of the alphabet, and you can then say anything you want. It is critical that the letters go in the right sequence, and spaces and sentence stops are used.
When our body makes new cells, it is placing the different letters of the DNA “alphabet” in the correct sequence. It has just 4 “letters”, the two base-Twins and their mirror images, to spell out all information. Sometimes errors occur!
There are different types of RNA, for slightly different functions. They include:
- ribosomal RNA (rRNA) structures. It changed little in the past millennia. It is thus used to trace relationships between different organisms, looking for common or divergent ancestors. rRNA is an organelle that makes the ribosomes. The molecular factory involved in this protein synthesis is called ribosimal rRNA. It is present in the cytoplasm and forms about 80% of the total RNA. The single-stranded molecule of rRNA is variously folded and twisted upon itself.
- transfer RNA (tRNA) molecules, have a group of 3 bases that are complementary to a mRNA codon group. Each specific tRNA molecule has one specific amino acid attached to it. After delivering this amino acid to the mRNA chain, the tRNA moves away from the ribosome to find another amino acid of the same make and waits with binding to the ribosome again until that specific amino acid is called for by the mRNA chain.
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messenger RNA (mRNA) molecules. mRNA is produced when the twin DNA strands are split in a process called Transcription. One strand is named RNA. Its base sequence is complementary to that of the DNA strand. See also the previous and the next page.
Non-coding RNAs are functional RNA molecules that are not translated into protein. Examples of this are rRNA & tRNA.
A transcription factor is a protein that binds to DNA and regulates gene expression by promoting or suppressing transcription.
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