1. Mutations Add to Table of Contents – p. 14

2. What Are Mutations? Changes in the nucleotide sequence of DNA
Results in a change in the amino acid sequence of a protein
Mutagen: something that causes a mutation
X-rays, Chemicals, & UV radiation are examples of mutagens

3. Are Mutations Helpful or Harmful?
Mutations happen regularly
Almost all mutations are neutral
Many mutations are repaired by enzymes

4. Are Mutations Helpful or Harmful?
Some types of skin cancers and leukemia result from mutations
Some mutations may improve an organism’s survival (beneficial)

5. Types of Mutations

6. 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.

7. Gene Mutations
Include:
Point
Insertion
Deletion

8. Point Mutation One nucleotide is substituted for another
Also known as substitution

9. Point Mutation
Sickle Cell disease is the result of one nucleotide substitution
Occurs in the hemoglobin gene

10. Frameshift Involves insertion or deletion of a nucleotide
Affects end polypeptide much more than a simple substitution

11. Insertion A nucleotide is added into the DNA sequence
THE CAT ATE THE RAT 
THE CAT TAT ETH ERA T

12. Deletion A nucleotide is deleted THE CAT ATE THE RAT 
THE CAT TET HER AT

13. Chromosome Mutations May Involve:
Changing the structure of a chromosome
The loss or gain of part of a chromosome
Include:
Inversion
Duplication
Translocation

14. Inversion
Chromosome segment breaks off, flips around backwards, and reattaches

15. Duplication
Occurs when a gene sequence is repeated

16. Translocation
Involves two chromosomes that aren’t homologous (do not match together)
Part of one chromosome is transferred to another chromosome

17. Nondisjunction Failure of chromosomes to separate during meiosis
Can cause a person to have too many or too few chromosomes

19. Chromosome Mutation Animation

21. Amino Acid Sequence Changed

22. Gene Mutation Animation

23. Identify the type of mutation given the original DNA sequence:
Identify the type of mutation given the original DNA sequence: ACGTACGCA 1.  ACGTCCGCA - point 2.  ACGTAGCA - deletion 3.  ACGTACAGCA - insertion 4.  ACGCATGCA - inversion 5.  ACGACGTACGCA - duplication 6.  TCGTACGCA – point 7.  ACATGCGCA - inversion