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Lecture 14

BIOL 1115 Lecture 14: Chapter 14

3 pages27 viewsFall 2016

Department
Biology
Course Code
BIOL 1115
Professor
terrikanner
Lecture
14

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Chapter 14
Mutation
o Heritable change in DNA
Good
Source of variation
Harmful
Cancer
o DNA repair systems
Gene mutations may affect amino acid sequences
o Silent mutation
o Missense mutation
o Nonsense mutation
o Frameshift mutation
Gene mutations outside of coding sequences
o Promoter mutation
May enhance or inhibit transcription
o Regulatory elements or operator site mutations
Operator mutation affects binding of a repressor protein
Germ-line or somatic cell mutations
o Time and location of a mutation
Determines its severity and the heritability
o Germ line cells
Gametes
o Somatic cells
Body cells
Spontaneous or induced mutations
o Spontaneous mutations
Cause biological process mistake
Background mutation rate 1 mutation / million genes
o Induced mutations
Cause: environmental agents
Mutagens
Chemical mutagens
o Disruption of base pairing
Some modify nucleotide structure
Nitrous acid
Mustard gas
o Disruption of replication
Benzopyrene
Physical mutagens
o Radiation damage
Ionizing radiation
High energy
Penetrates deeply
Creates free radicals
X-rays and gamma rays
Nonionizing radiation
Less energy and can only penetrate the surface
UV rays
Thymine dimers
Types of repair
o Direct repair
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