How can a mutation in DNA affect the protein that is built from a specific gene sequence?

Question

How can a mutation in DNA affect the protein that is built from a specific gene sequence? Describe a specific example to illustrate.
     

Answer 1

DNA codes for proteins. So, if the DNA is mutated, it directly affects the protein. Two examples of mutations are:



A point mutation. In this situation, one base pair (A, T, C, or G) is replaced with a different, incorrect one. When this happens and the DNA is read in order to synthesize a protein, this incorrect base pair can lead to the DNA codon (set of 3 base pairs) that codes for a different base pair than it should have. This causes the protein to have one incorrect amino acid in it. Also, this mutation does not always mutate the protein because some codons code for the same amino acid.



A frame shift mutation. This type is much worse. In this case, a base pair is just inserted in to the DNA sequence. When this happens, the entire sequence following it is essentially pushed over one spot. Then, each set of 3 base pairs that would code for an amino acid is shifted so that, instead, you would have something like 2 base pairs and 1 base pair from the codon next to it. This causes every single codon to mutate, which essentially leads to every amino acid being different and therefore, the entire protein being different.



I hope that made sense. Diagrams help.

Answer 2

A mutation could occur in an area that does not code for anything. A mutation can occur that codes for the same amino acid. A mutation can change one amino acid into a similar amino acid and so therefore does not significantly alter the proteins structure. Point mutations tend not to do much damage unless you switch to very different amino acid. One that makes sulfer bounds, Hydrophilic with hydrophobic. Deletions, additions, and exchanging DNA from other chromosomes do more damage. Your changing alot of Amino acids. Also some protein has multiple copies. If you damaged a DNA sequence, but there are other copies, the damage may not be bad, since the body has back up. The problem is the new DNA sequence will now code for something else, that might do damage, and If you need a lot of one protein, damage to one copy might affect the amount your body makes. Also the other thing is that if one cell is mutated and it isn't cancer, so what, You have other cells. If an egg or spem is mutated, it is even more important.

Answer 3

Point Mutation In Dna

Answer 4

I can't give a specific example, but each protein is coded by a series of 3-nucleotide groupings called codons. The nucleotides are what change in a mutation. Each nucleotide in a codon codes for one level of amino acid (the building block of protein) classification. If AGU codes for methionine and AAU codes for stopping the protein, a one-letter switch can decrease the length of the protein by half, thereby negating its purpose. Similarly, if one letter is swapped in say, the gene for eye color, that mutation will get copied into messenger RNA and brought to a "factory" for production. It might change your eyes from brown to canary yellow or something equally unusual.

Answer 5

Because the DNA sequence produces a specific protein. So say you have ABCD and that makes protein A, if you have a mutation that could make it ABDC and produce protein D, and result in not making the proper protein you need.