Unit 1.4 Mutations Flashcards
What are mutations
Rare & random changes in the DNA that can result in no protein or an altered protein being synthesised
The 2 types of mutation
Single gene & chromosome structure
What can increase the rate of mutation
Mutagenic agents
Examples of mutagenic agents
Mustard gas, X rays & UV light
What are genetic disorders
Conditions/ diseases that are directly related to an individuals genotype
What causes genetic disorders
Mutations in the DNA sequence
Where do gene mutations occur & what does this involve
Within genes & involves alterations to the DNA nucleotide sequence- this alters the sequence of bases on the DNA
What is single gene mutation
Change in one nucleotide
What are the 3 types of single gene mutations
Substitution, insertion & deletion
What happens in substitution
One nucleotide is swapped for another nucleotide
What can substitution result in
Missense, nonsense, or splice-site mutations
What does missense mutations result in
One amino acid being changed for another- which may result in a non-functioning protein or have little effect on the protein
What are nonsense mutations
Mutations that result in a premature stop codon being produced which results in a shorter protein
What are splice-site mutations
Mutations that result in some introns being retained and/or some exons not being included in the mature mRNA transcript
What can nucleotide insertions or deletions result in
Frame-shift mutations
