1. Mutations Changes to DNA

2. Learner Outcomes
I can explain how mutations may or may not impact the protein that is made in protein synthesis.
I can identify and explain the different types of mutations.

3. Standards Addressed:
Use mRNA codon charts to determine the effects of different types of mutations on amino acid sequence and protein structure (e.g., sickle cell anemia resulting from base substitution mutation) SC-HS SC-H-UD-S-3
SC-HS (DOK 3) Students will explain the role of DNA in protein synthesis. Cells store and use information to guide their functions. The genetic information stored in DNA directs the synthesis of the thousands of proteins that each cell requires. Errors that may occur during this process may result in mutations that may be harmful to the organism.

4. Mutations Changes to DNA are called mutations change the DNA
changes the mRNA
may change protein
may change trait
DNA
TACGCACATTTACGTACG
mRNA
AUGCGUGUAAAUGCAUGC aa
protein
trait

5. Types of mutations Changes to the letters (A,C,T,G bases) in the DNA
point mutation
change to ONE letter (base) in the DNA
may cause change to protein, may not
frameshift mutation
addition of a new letter (base) in the DNA sequence
deletion of a letter (base) in the DNA
both of these shift the DNA so it changes how the codons are read
big changes to protein!

6. Does this change the sentence?
Point Mutations
One base change
can change the meaning of the whole protein
THEFATCATANDTHEREDRATRAN
Does this change the sentence?
A LITTLE!
THEFATCARANDTHEREDRATRAN OR
THEFATCATENDTHEREDRATRAN

7. Does this change the protein?
Point Mutations
Missense mutation = changes amino acid
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Does this change the protein?
DEPENDS…
AUGCGUGUAUACGUAUGCGAGUGA
MetArgValTyrValCysGluStop

8. Misshapen sickle cells
Sickle cell anemia
Hemoglobin protein in red blood cells
strikes 1 out of 400 African Americans
limits activity, painful & may die young
Normal round cells
Misshapen sickle cells
Only 1 out of 146 amino acids

9. The code has repeats in it! Does this change the protein?
Point Mutations
Silent mutation = no change to protein
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
The code has repeats in it!
Does this change the protein?
Why not?
AUGCGUGUAUACGCUUGCGAGUGA
MetArgValTyrAlaCysGluStop

10. Really destroyed that protein!
Point Mutations
Nonsense mutation = change to STOP
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Really destroyed that protein!
AUGCGUGUAUAAGCAUGCGAGUGA
MetArgValStop

11. Does this change the sentence?
Frameshift Mutations
Add or delete one or more bases
changes the meaning of the whole protein
THEFATCATANDTHEREDRATRAN
Does this change the sentence?
A LOT!
Delete one!
Add one!
THEFATCANTANDTHEREDRATRAN OR
THEFATCAANDTHEREDRATRAN

12. Does this change the protein?
Frameshift Mutations
Addition = add one or more bases
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Does this change the protein?
A LOT!
AUGCGUGUAUACGUCAUGCGAGUGA
MetArgValTyrValMetArgValA

13. Does this change the protein?
Frameshift Mutations
Deletion = lose one or more bases
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Does this change the protein?
A LOT!
AUGCGUGUAUACGAUGCGAGUGA
MetArgValTyrAspAlaSerGA

14. Cystic fibrosis Broken salt channel in cells
strikes 1 in 2500 white births
gene codes for a protein channel that allows salt to flow across cell membrane
broken protein doesn’t work as channel
doesn’t allow salt out of cell, so water doesn’t flow out either
thicker & stickier mucus coating around cells
mucus build-ups in lungs & causes bacterial infections
destroys lung function
without treatment children die before 5; with treatment can live past their late 20s
Cystic fibrosis is an inherited disease that is relatively common in the U.S. Cystic fibrosis affects multiple parts of the body including the pancreas, the sweat glands, and the lungs. When someone has cystic fibrosis, they often have lots of lung problems. The cause of their lung problems is directly related to basic problems with diffusion and osmosis in the large airways of the lungs.
People without cystic fibrosis have a small layer of salt water in the large airways of their lungs. This layer of salt water is under the mucus layer which lines the airways. The mucus layer in the airways helps to clear dust and other inhaled particles from the lungs.

15. Deletion leads to Cystic fibrosis
Loss of one
amino acid!