Termination occurs when a stop codon is reached, the ribosome will end elongation and help fold the protein into its final structure. As each tRNA attaches and the ribosome moves along the mRNA, the amino acids on each tRNA are bonded into a longer and longer peptide chain and the now amino acid-less tRNA are ejected (elongation). Initiation involves the translation ribosome assembling around the mRNA starting at the 5' end start codon, and tRNA carrying an amino acid binding to the complimentary section of the mRNA. Translation involves three main steps - initiation, elongation, and termination.
There's also a stop codon before the end but I'll assume the same again. Normally, mRNA sequences start with "AUG" which is the start codon (and codes for Methionine), but I'll assume this is just for practice translating + transcribing in general. MRNA: 5'- GCU | AUU | CUA | AGA | CGG | UUA | UAC | UUU | CGG | CGC | CCC | AUG | UCG | AUU | UCU | CAU | UAA | CUU -3' We can then cross out each codon as we transcribe it and flip the sequence to be 5'-3' mRNA: Due to the length and the fact that we'll have to use triplets in translation anyways, it can help to break the sequence into triplet codons now.ĥ’-AAG | TTA | ATG | AGA | AAT | CGA | CAT | GGG | GCG | CCG | AAA | GTA | TAA | CCG | TCT | TAG | AAT | AGC-3’ In terms of transcribing the sequence given to you, we'll have to work backwards + flip it around to get the 5' to 3' mRNA since the DNA is given 5' to 3' rather than 3' to 5'.
The RNA polymerase will bind to the template DNA strand and synthesize the complimentary mRNA, substituting uracil for thymine (since RNA does not contain thymine like DNA). This process involves the enzyme "RNA polymerase," which can only add nucleotides to the 3' end of the mRNA, just like how DNA polymerase can only synthesize DNA in the 5' to 3' direction. So the central dogma of molecular biology describes the journey from DNA to protein product:ĭNA -transcription-> mRNA -translation-> ProteinĪssuming the DNA sequence provided is the template strand (rather than the complimentary coding strand), we start by transcribing the sequence into mRNA starting on the 3' end of the DNA towards the 5' end (which would build the mRNA 5' to 3').
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