7.5 Genetic Mutations Flashcards
genetic mutation
changes in DNA sequence
what can a genetic mutation be caused by?
-radiation
-chemicals
-replication errors
how can a genetic mutation affect a genome?
can change the structure and function of a genome
what are the 3 basic categories of mutations?
-mutations with positive effects
-mutations with negative effects
-mutations that do not cause any discernible changes
small scale mutations
Do not affect large portions of DNA
substitution
replacement of one base pair by another
insertion
addition of a base pair or larger coding region
deletion
removal of a base pair or larger coding region
inversion
bases switch positions
missense mutation
a mutation that changes a single amino acid in the coding sequence
nonsense mutation
a mutation that results in a premature stop codon
what are the types of substitution mutations?
missense
nonsense
silent
silent mutation
a mutation that does not alter the resulting amino acid sequence
frameshift mutation
a shift in the reading frame resulting in multiple missense/nonsense effects
-may occur from an insertion or deletion of a base pair
what are the types of large-scale mutations?
translocation
large scale deletions
large scale insertions
translocation
the movement of entire genes/sequences of DNA from one chromosone to another
large scale deletions
Can remove entire coding regions
Ex. Deletion of Dystrophin gene causes muscular
dystrophy
large scale insertions
The addition/duplication of large regions of DNA
Leads to a large number of the same gene
Provides opportunities for new genes to evolve
spontaneous mutations
caused by errors in DNA replication
induced mutations
caused by environmental effects
mutagen
an environmental agent that directly alters the DNA within a cell
how is carbon monoxide a chemical mutagen?
linked to various forms of cancer
how is benzene a chemical mutagen?
bonds to nucleotides and negatively affects replication
how is ethidium bromide a chemical mutagen?
inserts itself between strands of DNA and causes errors in replication
radiation
Electromagnetic radiation may cause mutations
Ultraviolet radiation may cause damage to DNA
and cause skin cancer
X-Rays/Gamma Rays can break bonds within DNA
molecules and cause cancer/super powers
