Mutations Unit 4 Chapter 12-4
Mutations
Jan 03, 2016
Mutations. Unit 4 Chapter 12-4. Learning goals. 1. Explain what a mutation is and how it can affect an organism. 2. Give the two types of cells where mutations can occur. 3. Describe the two types of gene mutations and give examples of each. Mutation. - PowerPoint PPT Presentation
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Mutations
Unit 4Chapter 12-4
Learning goals
• 1. Explain what a mutation is and how it can affect an organism.
• 2. Give the two types of cells where mutations can occur.
• 3. Describe the two types of gene mutations and give examples of each.
Mutation
• Mutation: permanent change in the DNA base sequences.
• Mutations can be good (rarely!) but usually are bad– 1. Good: make new traits– 2. Bad: change a protein structure
or gene activity
Where Mutations Occur
– Mutations in regular body cells•1. Occurs during mitosis•2. Affects the person, not the offspring•3. Affects the function of the cell
– This may cause cancer
– Mutations in making sex cells, (gametes = sperm or eggs)•1. Affects the offspring
not the person.•2. Usually is a disease.
– Ex. Tay Sachs disease, sickle-cell anemia, muscular dystrophy
Types of Mutations
• Gene Mutations: A change in the DNA sequence of a gene (2 types)– 1. Point Mutations: a change in a single base
pair in DNA • May cause change in one single amino acid or causes
no change at all. – NORMAL DNA
» DNA: TAC GCA TGG AAT» mRNA: AUG CGU ACC UUA» A.A.: Met-----ArgArg-----Thr-----
Leu– MUTATION
» DNA: TAC GTA TGG AAT» mRNA: AUG CAU ACC UUA» A.A.: Met-----HisHis-----Thr-----Leu
– 2. Frameshift Mutations: mutations that cause a change in the entire amino acid sequence following the mutation.
• Results from a Deletion or Insertion: when a single nucleotide is removed or added.
– EX: The fat cat ate the rat.» The atc ata tet her at
• Major effects! Can make protein useless.
• Chromosomal Mutations: Changes in number or structure of chromosomes.– 1. Deletion or duplication of a piece of
chromosome.– 2. Inversion: a piece of the chromosome
will detach and reattach in reverse order.– 3. Translocation: a piece of a chromosome
will break off and reattach to an entirely different chromosome.
Learning goals
• 1. Explain what a mutation is and how it can affect an organism.
• 2. Give the two types of cells where mutations can occur.
• 3. Describe the two types of gene mutations and give examples of each.
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