Mutations Flashcards
What are mutations?
They’re random changes to DNA.
They’re low frequency.
What are mutagenic agents?
Increase likelihood of mutations occurring.
Increase variety/new alleles.
e.g. mustard gas, x-rays/radiation, high temperature.
What are the single gene mutations?
Occur within genes.
Changes in DNA nucleotide sequence.
Result in altered proteins or no protein being produced.
What are the 3 types of gene mutations?
Deletion
Insertion
Substitution
What is deletion?
A nucleotide is removed.
Causes a major impact.
Affects all codons after mutation.
Referred to as a frame shift mutation.
What is insertion?
A nucleotide is inserted.
Causes major impact.
Affects all codons after mutation.
Referred to as a frame shift mutation.
What is substitution?
A nucleotide is replaced by another nucleotide.
Minor impact.
Affects only one codon and one amino acid after mutation.
Called a point mutation.
What is a missense mutation?
Missense mutations result in one amino acid being changed for another. This may result in a non-functional protein or have little effect on the protein.
What is a nonsense mutation?
Results in a premature stop codon being produced which results in a shorter protein.
What are splice site mutations?
A single gene mutation occurs at a splice site.
Results in an intron being left in or exons being removed from the mature mRNA.
Intron then affects protein structure and function.
What are the 4 types of chromosome mutations?
Translocation
Duplication
Deletion
Inversion
What is translocation?
Sections of one chromosome become attached to another chromosome.
What is inversion?
Section of chromosome is reversed.
What is duplication?
Sections of chromosomes are duplicated (repeated) from its homologous partner.
What is deletion?
A section of the chromosome is removed.
