Chapter 13.3 (Pgs. 372-376):Mutations

Mutations- Are heritable changes in genetic

information

- Have two major types:- Chromosomal mutations- Point mutations

- Can be harmful or beneficial

Chromosomal Mutations- Involve changes in the number or structure of

chromosomes

- Deletion- Loss of all or part of a chromosome

- Duplication- Produces an extra copy of all or part of a

chromosome

- Inversion- Reverses the direction of parts of a chromosome

- Translocation- Part of one chromosome breaks off and attaches

to another chromosome

Point Mutations

- Are mutations that involve changes in one or more nucleotides

- Occur at a single point in the DNA sequence

- Can cause changes to occur further along the DNA molecule from the initial mutation

Point Mutations- Substitution

- One nucleotide is changed to a different nucleotide

Sickle Cell Anemia

Point Mutations- Insertion or Deletion

- One nucleotide is inserted or removed from the DNA sequence

Huntington’s Disease

Muscular Dystrophy

Point Mutations- Frameshift

- Mutations that change the “reading frame” of DNA

- Change the sequence of DNA from the initial point of mutation

Causes of Mutations

- Include naturally-occuring errors - Can occur during replication

- Include chemical and physical agents in the environment, called mutagens- Chemicals- Radiation

Effects of Mutations- Can be harmful

- Change protein structure or gene activity in a negative way

- Sickle cell anemia

- Can be helpful- Change protein structure or gene

activity in a positive way- Increase disease resistance- Create better physiological function

- Some mutations have no effect at all