1. Mutation Notes:
Chapter 11

2. Mutations notes outline
Types at gene level
A. Point
B. Frameshift
which is worse?
Types at chromosome level
A. Deletion
B. Insertion
C. Inversion
D. Translocation
Causes
A. Random/spontaneous
B. Mutagen
Results
-, +, no effect

3. Mutation:
Mistake or change in DNA sequence

4. Types of mutations at the gene level:
Point:
change in a SINGLE base pair in DNA
Example:
ACTAGGCAC to ACTAGTCAC
Like:
the dog bit the CAT to the dog bit the CAR
Results in a change of one codon

5. The change in the DNA is minor but important

6. The effects of point mutations
mRNA
Normal
Protein
mRNA
Point
mutation
Protein

7. Frameshift mutations
A single base is added or deleted from DNA which shifts the reading of codons by one base.
ex. ACTAGGCAC to ACTAGAC
Like: The dog bit the cat to
The dob itt hec at

8. The results of frameshift mutations can be HUGE since every codon after the mistake is affected!

9. Frameshift mutations Without mutation Deletion of U
mRNA
Protein

10. Point vs. Frameshift Mutations
Which type of mutation is more serious?
Frameshift mutation affects every amino acid after the mutation
Point mutation affects only the amino acid at the mutation

12. Chromosomal Alterations
Chromosomal mutations--Structural changes in chromosomes
Are especially common in plants.
4 main types— Deletion, insertion, inversion, translocation

13. Types of chromosomal mutations:
Deletion:
part of a chromosome left out (usually deadly)
A B C E F G H
A B C D E F G H
Deletion

14. Types of chromosomal mutations:
Insertion:
additions to a chromosome
Usually from a sister chromatid

15. *Genes B and C were inserted into
Insertion
A B C D E F G H
A B C B C D E F G H
Insertion
*Genes B and C were inserted into
the chromosome*

16. Types of chromosomal mutations:
Inversion:
chromosome part breaks off and reattaches backwards
A B C D E F G H
A D C B E F G H
Inversion

17. Types of chromosomal mutations:
Translocation:
chromosome part breaks off and adds to another chromosome
Translocation

19. Causes of Mutations Spontaneous/Random mutations–
Some mutations just happen, (ie. mistake during DNA replication, transcription, mitosis, meiosis).
These lead to evolution.
Mutagen-- Any agent that causes a change in DNA
Include environmental factors like chemicals and radiation
Lead to birth defects if sex cells affected and cancer if body cells affected

20. Mutations can be: Negative: cause a structural or functional problem
Positive (very rare) ex. Can make the organism faster or stronger
Have no effect = silent mutation

21. Sometimes chromosomes fail to separate properly and result in extra or fewer chromosomes:
Down syndrome- extra chromosome # 21
Turner syndrome- missing X on 23rd pair

22. Inversion
Insertion
Deletion
Translocation