Protein Synthesis Lab


1. Translation:

Is the process in which the code carried by mRNA is converted into a polypeptide. There are multiple steps within the process. These steps are initiation, elongation, and termination


The mRNA binds to the small ribosomal unit (the bottom piece of the ribosome). The small and large ribosomal units then attach. The mRNA is actually the key to starting the entire process as the P-site must read the start codon AUG which permanently stays on the mRNA. In the image below, you are able to see the mRNA is being read by the P-site on the ribosome. This is the process of initiation and how it works.



The A-site reads the next codon in the mRNA and then it brings in matching complimentary tRNA, tRNA has 3 letter codes called anticodons that are complementary to the codons on the mRNA. The new tRNA binds to the P-site, and another one binds to the A-site. The amino acid in the A-site then let’s go of the tRNA in the A-site and binds to the neighboring amino acid in the P-site. This is the process for elongation. The image below shows how the amino acids lets go of the tRNA in the A- site and binds to the neighboring amino acid in the P- site.



The mRNA is read by the ribosome also has what is called a stop codon. This codon is a signal for the ribosome to stop reading the mRNA and for the tRNA to stop binding there are no matches in the tRNA to go with the stop codon. After the stop codon has been read, no new amino acids are added to the chain. This leads the ribosome to split into the two units again. The fresh polypeptide is then released and ready for use. This is how the last process works.


2. The materials used in this lab showed really well how translation works and what the mRNA actually does. There were a few problems though the first on had to be that you are not able to see how the ribosome actually splits. And the other issue was that we only had one ribosomal unit and the actual process uses two. These were the only inaccurate things in this lab. It was a lot of fun building the chains of amino acids and exploring how everything in DNA and mRNA works.