Download Mutation Notes (12.4)

Mutations (12.4)
State Standard
2D. Describe the relationships between changes
in DNA and potential appearance of new traits
Chapter 12 Molecular Genetics
12.4 Gene Regulation and Mutation
Mutations
 A permanent change in the nucleotide
sequence of a cell’s DNA is called a
mutation.
 Types of mutations
 Insertion
 Deletion
 Substitution
Chapter 12 Molecular Genetics
12.4 Gene Regulation and Mutation
Causes of Mutation
 Mutations can either occur spontaneously
or be caused by mutagens.
Mutagen – Any agent that can harm DNA, causing
a mutation.
 Examples of Mutagens: chemicals, radiation,
x-rays, gamma rays, ultraviolet light, tobacco,
free radicals.
Chapter 12 Molecular Genetics
12.4 Gene Regulation and Mutation
Effects of Mutations
 Genetic Disorders (ex – Sickle Cell
disease, Cystic Fibrosis)
 Changes in shape & functionality of
proteins.
 Dysfunctional protein synthesis.
 Cancer
AAG CCC ATA TTT CGA AGA TAG
AAG CCC ATA TTT CGA AGA TAG
AAG CCC ATA TTT CGA AGA TAG
Chapter 12 Molecular Genetics
12.4 Gene Regulation and Mutation
Types of Mutations
 Substitution – 1 nucleotide base is
replaced with another.
 Insertion – an extra nucleotide is inserted
in the DNA sequence.
 Deletion – 1 nucleotide base is left out of
the DNA sequence.
 Insertions & deletions cause frameshifts,
which throw off the whole DNA code for that
section.
Chapter 12 Molecular Genetics
12.4 Gene Regulation and Mutation
Chapter 12 Molecular Genetics
12.4 Gene Regulation and Mutation
Body-cell v. Sex-cell Mutation
 Somatic (body) cell mutations are not
passed on to the next generation.
 Mutations that occur in sex cells are passed
on to the organism’s offspring and will be
present in every cell of the offspring.
Chapter 12 Molecular Genetics
12.4 Formative
Questions
What is an immediate result of a mutation
in a gene?
0%
0%
C
A
B
C
D
B
A
0%
1.
2.
3.
4.
0%
D
A. cancer
B. genetic disorder
C. nonfunctional enzyme
D. amino acid deficiency
Chapter 12 Molecular Genetics
12.4 Formative
Questions
Which is the most highly mutagenic?
0%
0%
C
A
B
C
D
B
A
0%
1.
2.
3.
4.
0%
D
A. chemicals in food
B. cigarette smoke
C. ultraviolet radiation
D. X rays
Chapter 12 Molecular Genetics
Chapter Assessment
Questions
Explain the difference between body-cell and
sex-cell mutation.
Answer: A mutagen in a body cell becomes
part of the of the genetic sequence
in that cell and in future daughter
cells. The cell may die or simply not
perform its normal function. These
mutations are not passed on to the
next generation. When mutations
occur in sex cells, they will be
present in every cell of the offspring.
Chapter 12 Molecular Genetics
Standardized Test
Practice
What type of mutation results in this change
in the DNA sequence?
TTCTGG
A
0%
0%
A
B
C
D
0%
0%
D
1.
2.
3.
4.
C
A. deletion
B. frameshift
C. insertion
D. substitution
B
TTCAGG
Chapter 12 Molecular Genetics
Standardized Test
Practice
The structure of a
protein can be altered
dramatically by the
exchange of a single
amino acid for another.
A
B
0%
B
0%
A
A. True
B. False
1.
2.