1. CH. 11.6 Mutations in Genes Objectives: 1.Describe the following types of mutations: a.Base substitution b.Base insertion or deletion 2. Explain what can cause a mutation. Vocabulary: Mutation Mutagen

2. Mutations http://www.ptbeach.com/167020813143947783/cwp/view.asp?A=3&Q=278050&C=5459 0http://www.ptbeach.com/167020813143947783/cwp/view.asp?A=3&Q=278050&C=5459 0 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mutations.html Any change in nucleotide sequence of DNA Effects vary: None --> Severe

3. Base Substitutions http://www.ptbeach.com/167020813143947783/cwp/view.asp?A=3&Q=278050&C=54590 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mutations.html Single Base Mutation (Point Mutation) Replacement of one base or nucleotide for another. May or may not cause dysfunction in protein.

4. Base Substitutions http://www.ptbeach.com/167020813143947783/cwp/view.asp?A=3&Q=278050&C=54590 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mutations.html 1. Silent Mutation: Substitution does not result in a change in amino acid sequence. (More than 1 codon for each amino acid) Ex: GAA --> GAG still makes Glutamine

5. Base Substitutions 2. Missense Mutation: Substitution DOES result in an amino acid substitution. Can have negative effects. Sickle Cell Anemia

6. Sickled R.B.C.s are angular and inflexible Get stuck in blood vessels and block blood flow (=PAIN). Less functioning RBCs = Fatigue (limits O2 delivered to cells) http://www.nhlbi.nih.gov/health/health-topics/topics/sca/

7. Base Substitutions 3. Nonsense Mutation: Substitution results in a STOP CODON. Shorter, incomplete protein Negative impacts vary (How much protein was translated?)

8. Mutations: INSERTIONS & DELETIONS “Frameshift” mutations: Nucleotide is added or removed. Changes codons, changes amino acid sequence Bigger impacts/ Different Proteins

10. Review Mutations

11. Mutagens: Cause Mutations Physical Agents High frequency energy X-rays UV rays Chemical Agents Free-radical oxygens Certain chemicals (chemotherapy)

12. Mutations: Source of Genetic Variation Mutations are passed to offspring. Most lead to dysfunctional proteins. Some are lethal. Few - are beneficial (but important to gene pool) Variations in gene pool allow species to survive when environmental conditions change.