Mutation – any change in DNA sequence Can be caused by errors inside the cell◦ Errors in

Replication Transcription Cell division (mitosis, meiosis)

Outside Cuases of mutations = mutagens◦ Radiation (x-rays, UV, nuclear, etc.)◦ Chemicals (asbestos, formaldehyde, dioxins)

◦ High temperatures

Repair mechanisms –◦ Proofreading enzymes try to replace incorrect nucleotides

earthobservatory.nasa.gov/.../dna_mutation.gif

Depends on the type of cell…◦ Mutations in Reproductive Cells (sperm or egg) will be passed to offspring.

◦ Mutations in all other cells will only be passed to future cells but NOT offspring. Can cause problems for individuals

THE DOG BIT THE CAT

THE DOG BIT THE CAR(Point Mutation)

THE DOB ITT HEC AR(Frameshift Mutation)

Types of Mutations –1. Point Mutations: change in single base pair

May cause change in one amino acid.

2. Frameshift Mutations: shifts the reading of the mRNA codonsa.) Addition of a base b.) Deletion of a base

Deletion of an Adenine

Generally are more harmful than point mutation.

3. Chromosomal mutations: changes in chromosomes. Occurs during mitosis or meiosis Broken, joined to wrong C, deletion, duplication, inversion

Can cause the biggest problems.

Delection C #5 : Cri du chat-- R. T: some Down Syndrome