DNA Mistakes • DNA is a molecule that replicates, works and copies with very high accuracy • DNA has enzymes that make sure that it works with a high level of accuracy and detail • DNA can often work without mistake
DNA Mistakes • DNA can however make mistakes • When a DNA makes a mistake in its own sequence of base pairs its is called a mutation • A mutation can change the base pairs in DNA for the rest of DNA
DNA Mistakes • The process of making mutations is called mutagenesis • Mutagenesis is often the result of physical or chemical agents that can damage DNA called mutagens
Substitution • One of the types of mutations makes mistakes between the base pairs • When a base pair does not correctly match put with its complement it is a substitution mutation
Example Original Phrase: The cat ran over the hat. Mutation: cat bat New Phrase: The bat ran over the hat.
Substitution • If a substitution mutation is made, however there is no change in the amino acid sequence it is called a silent mutation • This is because the mutation in not seen • If the mutation does change the amino acid sequence it is called a missense mutation
Results of Mutations • Often times mistakes can change the stop codons for proteins • This means proteins either end early or don’t end at all • When a stop codon is changed and it changes the shape of an amino acid sequence it is called a nonsense mutation • This type of mutation can permanently change the organism
Substitution • By substituting a base pair for a different base pair will change the codon in the mRNA • By changing the codon there is a different amino acid that is coded • This changes the overall protein that is stored in DNA
Insertion and Deletion • Sometimes extra base pairs can be added or deleted from the DNA strand • These additions or decreases in base pairs can affect the entire molecule of DNA • This can change the message of DNA • These are called frameshift mutations
Example Original Phrase: The cat ran over the hat. Mutation: ran rn New Phrase: The cat rnovertheh at.
Insertion and Deletion • By adding and deleting base pairs there is a change in the overall codons for the protein • It could change some or all of the amino acids in the protein • Depending on where the insertion and deletion happens it could ensure that the protein never starts or stops
Results of Mutations • Mistakes in DNA often present themselves in single base pairs • One single base pair can change the message for an entire protein • These changes can change the proteins that DNA codes for
Results of Mutations • People often think about mutations in the way that the media presents mutations • People often think that mutation give people different personalities or powers http://www.youtube.com/watch?v=DI7q6DF6D54
Results of Mutations • Many times when a cell undergoes a mutation a cell becomes of less value • The cell cannot create a functional protein in a segment of DNA • This makes the cell less effective
Results of Mutations • Mutations also often lead to the death of a cell • Without an essential protein a cell will die • If the cell is very important, it could lead to the death of the organism
Mutations in Evolution • Mutations are not all bad • If the mutations give the organism some benefit the organism could live • The organism might actually benefit from the overall mutation