DNA mutations Flashcards
What is a mutation
the changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations.
What are the 3 types of mutation
Insertion
Deletion
Point mutation/ substitution
What is insertion
where one or more bases is inserted into the DNA strand
What is deletion
where one or more bases is deleted from the DNA strand
Why are insertion and deletion most problematic
They are frame-shift mutations
- when DNA is replicated, the sequence is read 3 bases at a time, as a codon, in a ‘reading frame’ so when a base is added or deleted the whole sequence of codons changes which proteins are being coded for
What is point mutation/ substitution
where a base is substituted that may or may not code for a different amino acid
Which process do enzymes undertake to reduce mutation
Mismatch repairs
What can cause mutations
UV radiation
X-rays
Gamma rays
What is a SNP
A single Nucleotide Polymorphism
- the act of a base pair being inserted, deleted or substituted (leading to a mutation of the organism)
What are the effects of mutations?
- no effect
- advantageous (peppered moth)
- disadvantageous - cancerous cells, sex cell mutations, etc
