1. MUTATIONS Mutations can occur in DNA replication Protein Synthesis

2. Replication Error Nondisjunction: chromosomes fail to properly separate during anaphase

3. Whole chromosome mutations: May be diagnosed by a karyotype. Examples: Down’s syndrome (trisomy), Turner’s syndrome (X0), Klinefelter’s syndrome (XXY)

4. Mutations can affect a single base, several bases, or an entire chromosome. Example: translocation

5. Mutations can occur during replication or protein synthesis. Mistakes could occur in either step TRANSCRIPTIONTRANSLATION Occurs inside the nucleus when the DNA strands separate Occurs in the cytoplasm at a ribosome mRNA is made using the DNA template, then it leaves the nucleus via a nuclear pore mRNA lined up at ribosome has “codon” (three base sequence) that the tRNA matches with an “anticodon”.

6. An error in base sequence in DNA or mRNA would result in the wrong amino acid.

7. Frameshift Mutations: reading errors cause insertions or deletions

8. 8 Making Proteins DNA DNA: TAC CGA TCG TGA ACT mRNA mRNA : AUG GCU AGC ACU UGA Protein Protein : Met-Ala-Ser-Thr-Stop Transcription Translation

9. 9 Effect of Mutation on Protein DNA DNA: TAC CGA TCG TGA ACT mRNA mRNA : AUG GCU AGC ACU UGA Protein Protein : Met-Ala-Ser-Thr-Stop Transcription Translation C G Gly

10. Point mutation: a single base is incorrect. Which amino acid would be delivered? Would every single base change result in a different amino acid?

11. Internal Mutations: a change in nucleotide sequence Occur during replication Usually fatal to the cell, but vital for increasing genetic variety Mutagen = agent that causes mutations (UV rays, chemicals, asbestos, cigarette smoke, etc.)

12. Types of Internal Mutations Changes in nucleotide sequence Are usually fatal to the cell, but vital for increasing genetic variety Types: