Do Now Check, in your notesDo Now Check, in your notes

Replicate this DNA strand: CATCGG

Transcribe this DNA strand in to RNA:CATAGG

Write 3 differences between DNA and RNA

V. MutationsV. Mutations

A. Introduction to MutationsA. Introduction to Mutations

-A mutation is a change in DNA sequence (order of nucleotides).

-Mutations are important because they increase genetic variation.

Mutations in Body CellsMutations in Body Cells

-Mutations in body cells cannot be passed on to your children, however, they can cause cancer or other problems in your body. A cancer cell.

Cancer as a result of mutations in Cancer as a result of mutations in body cells:body cells:

A person with skin cancer-This is why it’s important to always wear sunscreen!

Cancer as a result of mutations in Cancer as a result of mutations in body cells:body cells:

Tongue cancer and lung cancer are often caused by changes in body cells as a result of smoking, so don’t smoke!!!

Mutations in Reproductive (Sex) Mutations in Reproductive (Sex) CellsCells

-Mutations in sex cells (sperm and egg cells) can lead to changes in the DNA sequence which will can be passed down to a person’s children.

Mutations in sex cellsMutations in sex cells

-X-men and X-women would be a result of mutations in sex cells. These people inherited mutated (changed) DNA from their parents:

One last X-woman…One last X-woman…

Genetic DisorderGenetic Disorder

Some kinds of dwarfism can be inherited because of a mutation of a sex cell.

Good vs. Bad MutationsGood vs. Bad Mutations

Mutations can be good as well as bad. A good mutation could lead to a change in a protein that allows an animal to run faster or see better. A bad mutation could lead to a change in a protein that causes a genetic disease such as Sickle Cell Anemia or Hemophilia.

MutagensMutagens

A mutagen is something that causes a mutation.

Ex: radiation, chemicals, high temp.

ChernobylChernobyl

B. Gene MutationsB. Gene Mutations

There are 2 main types of gene mutations.

1. Point mutation1. Point mutation

-Point mutation-a change in one base pair in a DNA sequence.

-A point mutation can cause an amino acid to change, which will change the structure of the protein being made.

Example: AUG=Met AAG=Lys

-Only one letter was changed (the A to a U) and the entire amino acid changed (from methionine to lysine).

Picture of A Point MutationPicture of A Point Mutation

Normal

Point mutation

mRNA

ProteinStop

Stop

mRNA

Protein

Replace G with A

Point mutations in our lives!Point mutations in our lives!

-Sickle cell anemia is a blood disease caused by a point mutation.

-A single nucleotide is changed from “A” to “T” which causes the amino acid to change from glutamic acid to valine:

Amino acids: Thr – Pro – Glu – Glu

Normal: ACT CCT GAG GAG

Sickle cell: ACT CCT GTG GAG

Amino acids: Thr – Pro – Val – Glu

Point mutations in our lives!Point mutations in our lives!

-People with sickle cell anemia often experience a lot of pain and swelling and have trouble exercising.

Sickle cells do not move smoothly

through blood vessels like normal cells do.

Sickle cells get stuck and cause blood clots.

Sickle cells also can’t carry Oxygen as effectively as normal

Cells.

-Frameshift mutation-adding or deleting nucleotides to a DNA sequence.

-A frameshift mutation is much worse than a point mutation because it causes the entire DNA sequence to be shifted over!

Example: DNA: ATTAAACCG

ATAAACCG

2. Frameshift mutation2. Frameshift mutation

Delete this T

V. Frameshift mutationV. Frameshift mutation

mRNA

Protein

Frameshift mutation

Deletion of U

Frameshift MutationsFrameshift Mutations

Crohn’s Disease is caused by a frameshift mutation.

It causes inflammation to the digestive tract.

Difference between a point mutation Difference between a point mutation and a frameshift mutation.and a frameshift mutation.

Questions:Questions:

Is this a point mutation or a frameshift mutation?

-It’s a point mutation because only one nucleotide changed!

Questions:Questions:

THE DOG BIT THE CAT

THE DOG BIT THE CAR

Point or frameshift?

Point!

QuestionsQuestions

THE DOG BIT THE CAT

THE DOB ITT HEC AT

Point or frameshift?

-frameshift