Mutations
description
Transcript of Mutations
Mutations
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 rno vert heh 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
Video
http://www.youtube.com/watch?v=kp0esidDr-c
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
Practice