To make a protein, a cell's DNA goes from DNA to RNA to a protein. In transcription, the RNA polymerase reads and copies the DNA code as a messenger RNA (mRNA). The nest step is translation, in which the mRNA arrives at the ribosome in the cytoplasm and the ribosome reads the mRNA 3 bases at a time and translates the "DNA language" into "RNA language". The difference between "DNA language" ad "RNA language" is that the bases for the DNA consist of A, T, C, and G and RNA bases consist of a U instead of a T. Each 3-base sequence is called a codon which codes for one amino acid. The result of translation is a long chain of amino acids that twist and fold to become a protein.
Based on what I have seen about the effect on changing bases in DNA, the mutation that seemed to have the greatest effect on the proteins was deletion. Deletion completely changed the number of bases in the DNA sequence which affected the number of codons and amino acids. Deletion decreased the number of amino acids because it leaves two bases out that don't get to become an amino acid. The second mutation that would have a large effect on the proteins would be insertion. It, too, affects the number of bases in the code, but doesn't affect the number of amino acids that are made. It makes the same number of amino acids that the original code would make, but still changes the base sequence. The mutation that would have the least effect on the protein being made would be substitution. Substitution doesn't involve changing the number of bases in a DNA sequence, but still changes one base. Where the mutation occurs highly effects the proteins because the closer the mutation is to the beginning of the DNA, the more effect it will have on the protein. If the T that was changed was located near the end, it wouldn't have much effect on the amino acids that were to make the protein because not as many codons would have been changed. But since it was closer to the beginning, it affected all of the amino acids that came after it.
In Step 5 of the lab, I chose the mutation of deletion and placed it on the very first base because I wanted to see how much it would affect the whole protein. It turns out that it didn't even produce a protein because the start codon was changed and wasn't a start codon anymore. The deletion mutation is different from the other mutations because it produces one less amino acid to use for the protein. It matters where the mutation occurs because its location affects how much the protein will change depending on how close it is to the beginning of the sequence.
Progeria is a disease caused by a mutation in the DNA. I causes accelerated aging and most children who have it die around the young age of 13 from a heart attack or stroke. Symptoms of progeria include rigid skin, baldness on the whole body, bone abnormalities, and growth impairment.
Based on what I have seen about the effect on changing bases in DNA, the mutation that seemed to have the greatest effect on the proteins was deletion. Deletion completely changed the number of bases in the DNA sequence which affected the number of codons and amino acids. Deletion decreased the number of amino acids because it leaves two bases out that don't get to become an amino acid. The second mutation that would have a large effect on the proteins would be insertion. It, too, affects the number of bases in the code, but doesn't affect the number of amino acids that are made. It makes the same number of amino acids that the original code would make, but still changes the base sequence. The mutation that would have the least effect on the protein being made would be substitution. Substitution doesn't involve changing the number of bases in a DNA sequence, but still changes one base. Where the mutation occurs highly effects the proteins because the closer the mutation is to the beginning of the DNA, the more effect it will have on the protein. If the T that was changed was located near the end, it wouldn't have much effect on the amino acids that were to make the protein because not as many codons would have been changed. But since it was closer to the beginning, it affected all of the amino acids that came after it.
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| Insertion, deletion, and deletion examples. |
In Step 5 of the lab, I chose the mutation of deletion and placed it on the very first base because I wanted to see how much it would affect the whole protein. It turns out that it didn't even produce a protein because the start codon was changed and wasn't a start codon anymore. The deletion mutation is different from the other mutations because it produces one less amino acid to use for the protein. It matters where the mutation occurs because its location affects how much the protein will change depending on how close it is to the beginning of the sequence.
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| Deletion example with the first base removed. |
Progeria is a disease caused by a mutation in the DNA. I causes accelerated aging and most children who have it die around the young age of 13 from a heart attack or stroke. Symptoms of progeria include rigid skin, baldness on the whole body, bone abnormalities, and growth impairment.
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