Download Mutations Notes - Mr. Coleman`s Biology

Mutations Notes
Mutation
 A change in a nucleotide.
 Usually has a negative affect on an
organism, but occasionally can have a
positive effect, leading to the
organism being better suited to its
environment (adaptation).
Mutation (cont.)
 Mutations can happen in somatic
(body) cells or in gametes (sex cells).
 Only mutations in gametes can be
inherited.
Mutagen
 Factors that cause mutations.
 Mutagens can be chemical, radiation,
high temperature, X-Rays, or UV
light.
3 Types of Mutation
 Point Mutation: A change in a single
nucleotide.
 Frameshift Mutation: The addition or
deletion of a nucleotide or group of
nucleotides.
 Chromosomal Mutation: A change in
an entire gene or section of a
chromosome.
Point Mutations
 There are 3 types of point mutations,
Missense, Nonsense and Silent.
 Missense mutations are mutations that
cause a change in one amino acid.
 Nonsense mutations cause a premature
stop codon to appear in the DNA sequence.
 Silent mutations have a change in the DNA
sequence but no change in the amino acid
sequence.
Frameshift Mutations
 Insertion – when
one or more
nucleotides are
added to the
sequence, this
changes all of the
amino acids
following the
mutation
Frameshift Mutation (cont.)
 Deletion - when
one or more
nucleotides are
removed from the
sequence, this
changes all of the
amino acids
following the
mutation
Chromosomal Mutations
 Deletion – When one
or more genes are
removed from the
sequence.
 Duplication – When
one or more genes are
added to the
sequence.
 Inversion – When the
order of genes on the
chromosome is
changed.
 Translocation – When
genes from one
chromosome are
moved to another
chromosome.