Protein Synthesis Lab

In this lab, we asked the question, “How does the body produce proteins?” In the protein synthesis process, there are two steps — transcription and translation. Transcription occurs first, where one strand of the DNA is copied and makes RNA. Then the base thymine is replaced with uracil. After, the RNA is transported to the cytoplasm, where translation occurs. The ribosome in the cytoplasm reads the RNA in groups of three, or codons, where it forms amino acids. The amino acids then bond together to make proteins.

Changing bases in the DNA molecule result in either frameshift mutations or substitution. The frameshift mutations include insertion or deletion where a base is either added or deleted, and substitution replaces a base for another. In this lab, I noticed that the frameshift mutation had the most amount of change comparing it to substitution because by adding or deleting a base, the entire sequence is shifted and therefore changed, but in substitution, the one base that is being substituted is the only one being affected, so it wouldn’t affect the sequence by a great deal. However, the mutations are the most problematic and harmful when they occur at the beginning of the sequence, because the start codon could be changed, due to mutations, into the stop codon, making the amino acids unable to form into a protein.

In the experiment, I observed how the substitution mutation would affect the sequence. I substituted the start codon for a stop codon, which invalidated the protein because the protein was never able to form as it started with a stop codon, signalling the stopping of the process. Although this mutation greatly affected the protein, it was only because of where it occurred, rather than how the mutation occurred. Since only the first three bases were substituted, nothing happened to the rest of the codons as they stayed the same. But due to where the mutation was placed, it affected the protein, as the mutation I tested substituted the start codon for a stop codon.

Mutations are so common in life. However these mutations can have dramatic effects that can put the individual at great risk, or it can barely affect that individual at all. For example, the fatal disease called Tay-Sachs disease comes from the frameshift mutation on the gene that converts the alpha-subunit of the lysosomal enzyme, beta-hexosaminidase. This frameshift mutation is the cause of Tay-Sachs disease and cause the destruction of the nerve cells in the spinal cord and the brain, which has been shown to be fatal.