Embed Size (px)
DESCRIPTION
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. - PowerPoint PPT Presentation
Citation preview
Mutations
Unit 4Chapter 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-----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.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.
