Mutations

*Warm Up* Title page 81: Mutation Notes Title page 82: Mutation Critical Writing

Only answer #s 1, 2, 3, 4 Turn in to black files Pick up notes and glue on page 81.

Mutations A mutation is any change in DNA If DNA mutates, you change amino acids which changes ____________, which changes _______________. The more amino acids affected, the more severe the mutation. proteins traits

What causes mutations? Mutations can be caused by errors in replication, transcription, cell division, or by external agents. What are some external agents that could cause a mutation?

11.3 Section Summary 6.3 – pages 296 - 301 Causes of Mutations Any agent that can cause a change in DNA is called a mutagen. Mutagens include radiation, chemicals, and even high temperatures. Forms of radiation, such as X rays, cosmic rays, ultraviolet light, and nuclear radiation, are dangerous mutagens because the energy they contain can damage or break apart DNA. 11.3 Section Summary 6.3 – pages 296 - 301

Mutations in reproductive cells Mutations can affect the reproductive cells of an organism by changing the sequence of nucleotides within a gene in a sperm or an egg cell. Reproductive cells are egg and sperm Egg and sperm are referred to as GAMETES. If this cell takes part in fertilization, the altered gene would become part of the genetic makeup of the offspring.

Mutations in body cells Damage to a gene may impair the function of the cell. Body cells are any cell that are NOT gametes. Body cells are referred to as SOMATIC cells When that cell divides, the new cells also will have the same mutation. Some mutations of DNA in body cells affect genes that control cell division. This can result in the cells growing and dividing rapidly, producing cancer.

Mutation must occur in a gamete for it to be hereditary.

Types of Mutations Point Mutations Frameshift Mutations Chromosomal Mutations

11.3 Section Summary 6.3 – pages 296 - 301 The effects of point mutations A point mutation is a change in a single base pair in DNA. Usually changes 1 amino acid Normal: THE DOG BIT THE CAT Mutated: THE DOG BIT THE CAR A change in a single nitrogenous base can change the entire structure of a protein because a change in a single amino acid can affect the shape of the protein. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Point Mutations mRNA Normal Protein Stop Replace G with A Point mutation mRNA Protein Stop 11.3 Section Summary 6.3 – pages 296 - 301

Point Mutation Diseases Cystic fibrosis Sickle Cell anemia

11.3 Section Summary 6.3 – pages 296 - 301 Frameshift mutations Two types of frameshift mutations: Insertion or deletion of nitrogen bases THE DOG BIT THE CAT THE DOB ITT HEC AT DNA is read in groups of 3’s so when an addition or deletion occurs, the other nitrogen bases must shift over to fill the hole Changes all amino acids after the mutation 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Frameshift mutations Deletion of U Frameshift mutation mRNA Protein 11.3 Section Summary 6.3 – pages 296 - 301

Frameshift Mutation Diseases Tay Sachs

Chromosomal Mutations Extra or missing all or part of a chromosome Chromosomes contain millions of nitrogen bases which affect 1000’s of amino acids

Chromosomal Mutation Diseases Down’s Syndrome – 1 extra 21st chromosome Turner Syndrome – missing an X chromosome

2 Instances when a mutation will NOT cause an issue: If the mutation results in the same amino acid UCU and UCC both code for serine

Mutation Critical Writing Sentence Starters: What is a mutation? What are the types of mutations? What can mutations cause? How can a mutation be passed down to your child?