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Mutations. Unit 4 Chapter 12-4. Learning goals. 1. Explain what a mutation is and how it can affect an organism. 2. Name the two types of cells where mutations can occur and the affects. 3. Describe the two types of gene mutations and give examples of each. Mutation.
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Mutations Unit 4 Chapter 12-4
Learning goals • 1. Explain what a mutation is and how it can affect an organism. • 2. Name the two types of cells where mutations can occur and the affects. • 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 occur in regular body cells • 1. Occurs during mitosis (cell division) • 2. Affects the person, not the offspring • 3. Affects the function of the cell • This may cause cancer
Mutations occur in sex cells (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 in DNA • May cause a change in one single amino acid or cause no change at all. • NORMAL DNA • DNA: TAC GCA TGG AAT • mRNA: AUG CGU ACC UUA • A.A.: Met-----Arg-----Thr-----Leu • MUTATION • DNA: TAC GTA TGG AAT • mRNA: AUG CAU ACC UUA • A.A.: Met-----His-----Thr-----Leu
2. Frameshift Mutations: mutations that cause a change in the entire amino acid sequence following the mutation. Two Types: • 1. Deletion mutation: when a single nucleotide is removed • EX: The fat cat ate the rat. • The atc ata tet her at • 2. Insertion mutation: when a single nucleotide is added • EX: The fat cat ate the rat. • The fat sca tat eth era t • Major effects! May alter the function of a protein.
Chromosomal Mutations: Changes the 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. Name the two types of cells where mutations can occur and the affects. • 3. Describe the two types of gene mutations and give examples of each.