unit 1.4: mutations Flashcards
what are mutations
a change in the structure of an organisms DNA
what can mutations result in
no protein being formed
altered protein being formed
what is the estimation of mutations to base pairs
1 per 15-30million
what are the examples of mutagenic agents
mustard gas
UV light
gamma rays
X rays
what are the two main types of mutations
single gene mutations
chromosome structure mutations
what are the 3 single gene mutations
substitution
insertion
deletion
what does insertion involve
a nucleotide with a particular base is added inserted into the gene changing the order of the amino acids
what does deletion involve
a nucleotide with a particular base is removed changing the order of the amino acids
what does substitution involve
a nucleotide with a particular base is swapped with a different base
what are the 3 single nucleotide substitutions that can form
non-sense
mis-sense
splice-site
what is an example of a nonsense mutation
duchenne muscular dystrophy
what is an example of a missense mutation
sickle-cell disease
what is an example of splice site mutations
beta-thalassemia
what is a nonsense mutation
the substitute results in a premature stop codon being produced which results in a shorter protein, likely to be non-functional
what is a missense mutation
one amino acid is changed for another, this amino acid may result in a non-functional protein being produced, or having little effect on the protein
what is a splice site mutation
may occur during splicing where introns are retains however exons are removed from the mature mRNA transcript, this can result in a non functional protein being produced
what is insertion and deletion also known as
frame-shift mutations
what is a frame-shift mutation
where all bases from the mutation point are changed, this has a major effect on the protein structure
what are examples of a frame-shift mutation
huntington’s disease
fragile X syndrome
what are the 4 chromosomal structure mutations
deletion
inversion
duplication
translocation
what is an example of deletion mutations
cri du chat syndrome
what is a chromosome deletion mutation
genes are removed from a section of a chromosome
what chromosome are genes deleted from that results in cri du chat
chromosome 5
what is an example of inversion mutations
non-viable gametes
