STEP 3 Eventually , after elongation has proceeded for some time , the ribosome comes to a stop codon ( UAA , UAG , or UGA ), which signals the end of the mRNA message . As a result , the ribosome releases the polypeptide chain , detaches from the mRNA strand , and dissociates into two separate subunits . The mRNA strand is then degraded and its nucleotides become available for another transcription process . In this way , a protein comes to be produced !
AMINO ACIDS PEPTIDE PROTEIN
What happens after translation ? For many proteins , translation is only the first step in their life cycle . Moderate to extensive post-translational modification is sometimes required before a protein is complete . Once complete , the new protein ' folds ' into a distinct three-dimensional structure . Some proteins go on to become enzymes that catalyze biochemical reactions . Some play roles in DNA replication and transcription . Others provide structural support for the cell or carry out one of many other important cellular support functions .
If all cells have the same DNA , why do they have different functions ? Each of the more than 37.2 trillion cells in the human body contains the same genome - the same number of chromosomes , the same 25,000 genes , and the same 3.2 billion DNA nucleotide bases .
However , each of the 200 cell types in our bodies interprets this identical information very differently in order to perform the functions necessary to keep us alive . That is because the function of a cell is defined by its transcriptome . A transcriptome is the full range of mRNA molecules ( all exons , no introns ) expressed by a cell . Every cell has a unique recipe for which genes are turned on , when , and for how long . A cell ’ s transcriptome ultimately determines what type of cell it becomes ( neuron , hepatocyte , red blood cell , etc .), what proteins it produces , and how precisely it functions .
The process of turning on a gene to produce RNA and protein is called gene expression . Every cell , whether a simple unicellular organism or a complex multicellular organism , controls when and how its genes are expressed . This allows them the flexibility to adapt to damage and / or a changing environment .