Mutations!!!

1. Mutations!!!

2. Don’t forget……………… What nitrogen base pairs with Adenine? What nitrogen base pairs with Guanine? What is the name given for every set of three nitrogen bases on the DNA? What does one codon code for? When amino acids bond together, what do they form?

3. Gene Mutations • Mutations are changes in genetic material or DNA, and they can occur • during DNA replication • One in every billion base pairs is mutated • The average person has 6 mutations in each cell • Mutations are a major source of variation in a population and can help • organisms evolve (change over time) • Mutations in gametes are passed on to offspring • Mutations in body cells only affect the organism in which they • occur and are not passed on to offspring

4. ? If we have that many mutations and the some can be harmful, why don’t we look weird? Mutations are not always seen. Every part of your DNA doesn’t make a protein or trait. Remember this is called “junk DNA”.

5. Mutations affect protein synthesis Transcription: Mutated DNA will produce faulty mRNA leading to the production of a bad protein.

6. Types of mutations pages 307-308 Chromosomal: affecting whole or a part of a chromosome Gene: changes to the bases in the DNA of one gene

7. Gene Mutations • Change in the nucleotide sequence of a gene • May only involve a single nucleotide • May be due to copying errors, chemicals, viruses, etc.

8. } Also called Frameshift Mutations Types of Gene Mutations Point Mutation - involve changes in one or more nucleotides in DNA There are three types: • Substitution 2. Deletion 3. Insertion

9. Types of Point Mutations: Substitution Insertion Deletion

10. Substitution -one base is changed to another. • Usually affects a single amino acid in a protein or it may cause • no change in the amino acid • Has the least harmful affect An example of substitution mutations is sickle cell anemia. One amino acid changes in the hemoglobin, but the hemoglobin still functions in the RBC, just not as well.

11. Frameshift Mutations – changes that cause every codon that follows the mutation to shift position • A base is inserted or removed from DNA sequence • Insertion and deletion mutations have the most effect on an • organism because they affect many amino acids on the protein, • not just one. Huntington’s Disease is caused by an insertion mutation. People with this disorder have involuntary movement and loss of motor control. They eventually have memory loss. The disease is terminal and similar to Parkinson’s Disease, another motor loss syndrome.