Once upon a time, there was another DNA molecule, this time inside of a bacterium. This DNA decided that she wanted to create a new friend that was like her best friend but a little different and much smaller. This new friend would be called RNA, and through gene expression, would create a polypeptide.
DNA decided, that in order to insure the completion of gene expression, she would create messenger RNA that would be called mRNA for short. The process of created this new mRNA was called transcription and would use the information DNA possessed.
First, DNA had to decide which gene to transcribe, and because it was her first time transcribing RNA, she decided to transcribe a short gene. The coding portion of the gene was 3’-TACTTACTCACT-5’. …show more content…
There were U’s instead of T’s because in RNA, uracil replaces thymine.
Had this DNA been in a eukaryotic cell, the process would not have been quite so simple. At termination, there would have been a polyadenylation signal sequence. About 10-35 nucleotides later, the RNA would be cut loose and transcription would end.
In a eukaryote, the process wouldn’t have ended yet. Now, it would be time for RNA processing, the modification of pre-mRNA, also known as the primary transcript, before it is sent out into the cytoplasm.
First, a modified form of guanine called a 5’ cap would be added to the 5’ end, and a string of A’s called the poly-A tail would be added to the 3’ end. Next, RNA splicing, the removing introns, generally non-coding of areas of the gene, would be catalyzed by the spliceosome, a large complex of proteins and small ribosomes that cuts introns out of mRNA. This process could also be catalyzed by a ribozyme, an RNA molecule that also functioned as enzymes. Many ribozymes are interns that cut themselves out of a pre-mRNA sequence. This would result in a shorter mRNA that had modified ends and only exons, the portions of the mRNA that would eventually leave the
DNA decided, that in order to insure the completion of gene expression, she would create messenger RNA that would be called mRNA for short. The process of created this new mRNA was called transcription and would use the information DNA possessed.
First, DNA had to decide which gene to transcribe, and because it was her first time transcribing RNA, she decided to transcribe a short gene. The coding portion of the gene was 3’-TACTTACTCACT-5’. …show more content…
There were U’s instead of T’s because in RNA, uracil replaces thymine.
Had this DNA been in a eukaryotic cell, the process would not have been quite so simple. At termination, there would have been a polyadenylation signal sequence. About 10-35 nucleotides later, the RNA would be cut loose and transcription would end.
In a eukaryote, the process wouldn’t have ended yet. Now, it would be time for RNA processing, the modification of pre-mRNA, also known as the primary transcript, before it is sent out into the cytoplasm.
First, a modified form of guanine called a 5’ cap would be added to the 5’ end, and a string of A’s called the poly-A tail would be added to the 3’ end. Next, RNA splicing, the removing introns, generally non-coding of areas of the gene, would be catalyzed by the spliceosome, a large complex of proteins and small ribosomes that cuts introns out of mRNA. This process could also be catalyzed by a ribozyme, an RNA molecule that also functioned as enzymes. Many ribozymes are interns that cut themselves out of a pre-mRNA sequence. This would result in a shorter mRNA that had modified ends and only exons, the portions of the mRNA that would eventually leave the