1. When our DNA has mistakes!
DNA Mutations
When our DNA has mistakes!
Copy everything in BLUE on Page

2. A DNA MUTATION is a change or mistake in the DNA sequence that may or may not affect the proteins.3’ 5’

3. Causes of DNA Mutations
Environmental Factors
(UV light, radiation, chemicals, etc.)
2. Mistakes during DNA replication – TRANSCRIPTION MISTAKES DON’T COUNT!!
NOTE: DNA polymerase makes about 1 mistake in every 50 MILLION bases during replication!!

4. Substitution (AKA Point Mutation):
3 Types of Mutations
Substitution (AKA Point Mutation):
Substitute = take out something and replace it with another
What does substitute mean?
Hemoglobin is the protein in blood that carries oxygen.

5. Map of Malaria Cases
Sickle cell anemia produces a deformed hemoglobin protein, which deforms the red blood cell itself. The red blood cell is no longer fat squishy and round, it is not hard, sticky and sharp. It’s in the shape of a sickle, a type of curved ax. People can get a “sickle cell crisis,” a very painful condition that lasts a few days. However, sickle cell prevents against malaria, which kills millions of children by attacking their red blood cells. Malaria is found in tropical places like Africa, Central America, India, etc.
Map of Sickle Cell Cases

6. Substitution/Point Mutation:
when one or more DNA bases are replaced G A T A C G T T C A G 3’ 5’
Original or Normal DNA
Mutated DNA
If you have a mutation in your DNA…
It could change your mRNA…
It could change the amino acid…
It could change the protein!

7. An English Example…
Normal: THE MAN SAW THE DOG EAT THE RUG Point Mutation: THE MAN SAW THE FOG EAT THE RUG

8. 2. Deletion Mutation: when one or more DNA bases are deleted
Frameshift Mutations
2. Deletion Mutation:
when one or more DNA bases are deleted
Delete = to take away something!
What does delete mean?
CYSTIC FIBROSIS
Normal CFTR Sequence:
Nucleotide A T C A T C T T T G G T G T T
Amino Acid Ile Ile Phe - Gly Val
Abnormal CFTR Sequence:
Nucleotide A T C A T T G G T G T T
Amino Acid Ile Ile Gly Val T A G 3’ C C T G A 5’
If you have a mutation in your DNA…
It could change your mRNA…
It could change the amino acid…
It could change the protein!

9. MUCUS Healthy Cystic Fibrosis Cystic Fibrosis
CFTR protein is a chloride ion channel on the cell membrane of many mucous membranes throughout the body. The deletion affects the hydrophobicity of the channel (I think?) so it does not work properly. The chloride will not be balanced on both sides of the cell, and therefore water will not be balanced… The mucus stays thick and sticky instead of watered down.
Healthy
Cystic Fibrosis

10. An English Example…
Normal: the man saW the dog eat the rug Deletion Mutation: the man sat hed oge att her ug

11. 3. Insertion Mutation: 3’ 5’ when one or more DNA bases are added
Frameshift Mutations
3. Insertion Mutation:
when one or more DNA bases are added
Insert = add something into another object
What is does insert mean? G A T A C G T T C A G 3’ 5’
If you have a mutation in your DNA…
It could change your mRNA…
It could change the amino acid…
It could change the protein!

12. An English Example…
Normal: THE MAN SAW THE DOG EAT THE RUG Insertion Mutation: THE MAN SAW THE FAT DOG EAT THE RUG

13. Effects of Mutations
Mutations can be…
Neutral (no effect)
Beneficial (good)
Harmful (bad)
Sickle Cell Anemia!
Cystic Fibrosis!
Possible HIV cure??
NOTE: Most mutations are neutral because it usually does not affect the amino acid.
CCR5 – receptor protein on surface of T-cell, which allows some strains of HIV to attach and infect the T-cell. However, because of a deletion mutation the CCR5 gene, the protein is mutated and certain strains of HIV cannot recognize the T-cells. Mutation may have evolved in Europe during Bubonic plague (bc it also prevents bubonic plague). Research is being done now (2009).

14. Why are most DNA mutations neutral?
There are many possible codons for the same amino acid!
Most likely the protein will not be affected.
DNA can also repair itself.
A mistake may happen in a “recipe” that the cell does not use.
A few mistakes is minor in comparison to the 6 billion bases you have!

15. Will mutations be passed on to their children?
Only if the DNA mutation is in the testes or ovaries (sex cells)!
A mutation in any other
cell only affects parent.
We will talk about
chromosome disorders later.

16. Practice Problem MIND CONTROL! NORMAL DNA: A A G – G G C – A C C
Protein
Result
Phe – Pro – Trp
Normal
Phe – Ser– Arg
Mind Control
Phe – Arg
Telekinesis
Phe – Trp
X-Ray Vision
Phe – Ser – Trp
Superhuman Strength
Oh no, Ms. Becerra’s DNA polymerase made a mistake! This caused a substitution mutation in her DNA. Replace Normal DNA Base #4 with an A, and replace #7 with an T.
NORMAL DNA: A A G – G G C – A C C
Type of Mutation:
MUTATED DNA:
NEW RNA:
NEW PROTEIN:
Substitution Mutation
MIND
CONTROL!
A A G – A G C – T C C
U U C – U C G – A G G
Phe – Ser – Arg

17. TERATOMA!!!

18. Learning Log – 11/30 – Page 72 need to know warm up
Copy the following:
How to read mutation problems carefully!
Answer the following:
What type of mutation happened below?
Normal DNA: TATGGCAAC
Mutant DNA: TATGCAAC

19. Learning Log – 12/2 – Page 72 need to know warm up Copy the following:
Review: How does protein synthesis happen in the cell?
Answer the following:
What happens to a protein after it’s made?
RKT powerpoint

20. Learning Log – 12/3 – Page 72 need to know warm up Copy the following:
Why do we have different cells even though the DNA (instructions) are the same?
NONE – WONDERWALL!

21. New Life Form??