Download Mutations - Northwest ISD Moodle

Mutations
*Warm Up*
• Title page 81: Mutation Notes
• Title page 82: Mutation Critical Writing
•Only answer #s 1, 2, 3, 4
•Turn in to black files
•Pick up notes and glue on page 81.
Mutations
• A mutation is any change in DNA
• If DNA mutates, you change amino acids
proteins
which changes ____________,
which changes
traits
_______________.
• The more amino acids affected, the more
severe the mutation.
What causes mutations?
• Mutations can be caused by errors in replication,
transcription, cell division, or by external agents.
• What are some external agents that could cause a
mutation?
Causes of Mutations
Any agent that can cause a change in DNA is called a
mutagen.
Mutagens include radiation, chemicals, and even high
temperatures.
Forms of radiation, such as X rays, cosmic rays,
ultraviolet light, and nuclear radiation, are dangerous
mutagens because the energy they contain can
damage or break apart DNA.
Mutations in reproductive cells
• Mutations can affect the reproductive cells of an
organism
by changing
the
sequence
of sperm
Reproductive
cells
are
egg
and
nucleotides within a gene in a sperm or an egg
cell.
Egg
and sperm are referred to as GAMETES.
• If this cell takes part in fertilization, the altered
gene would become part of the genetic makeup
of the offspring.
Mutations in body cells
• Damage to a gene may impair the function of the
cell.
Body
cells
are
any
cell
that
are
NOT
• When that cell divides, the new cells also will have
gametes.
the same mutation.
Body
cells
are referred
as cells
SOMATIC
cells
• Some
mutations
of DNA in to
body
affect genes
that control cell division.
• This can result in the cells growing and dividing
rapidly, producing cancer.
Mutation must occur in a gamete for it
to be hereditary.
Types of Mutations
• Point Mutations
• Frameshift Mutations
• Chromosomal Mutations
The effects of point mutations
• A point mutation is a change in a single base pair in
DNA.
• Usually changes 1 amino acid
Normal:
THE DOG BIT THE CAT
Mutated:
THE DOG BIT THE CAR
A change in a single nitrogenous base can change
the entire structure of a protein because a change
in a single amino acid can affect the shape of the
protein.
Point Mutations
mRNA
Normal
Protein
Stop
Replace G with A
mRNA
Point
mutation Protein
Stop
Point Mutation Diseases
• Cystic fibrosis
• Sickle Cell anemia
Frameshift mutations
• Two types of frameshift mutations: Insertion or
deletion of nitrogen bases
THE DOG BIT THE CAT
THE DOB ITT HEC AT
• DNA is read in groups of 3’s so when an addition or
deletion occurs, the other nitrogen bases must shift
over to fill the hole
• Changes all amino acids after the mutation
Frameshift mutations
Deletion of U
Frameshift
mutation
mRNA
Protein
Frameshift Mutation Diseases
• Tay Sachs
Chromosomal Mutations
• Extra or missing all or part of a chromosome
• Chromosomes contain millions of nitrogen
bases which affect 1000’s of amino acids
Chromosomal Mutation Diseases
• Down’s Syndrome –
1 extra 21st
chromosome
• Turner Syndrome –
missing an X
chromosome
2 Instances when a mutation will NOT
cause an issue:
• If the mutation results in the same amino
acid
• UCU and UCC both code for serine
Mutation Critical Writing
Sentence Starters:
• What is a mutation?
• What are the types of mutations?
• What can mutations cause?
• How can a mutation be passed down to your child?