Mutations (Biology 016) Flashcards
What is a mutation
A permanent change in the base sequence of DNA
What are the two types of gene mutations
Point mutation and frameshift mutation
What happens in point mutation
One nucleotide is replaced with another nucleotide
What happens in frameshift mutation
One or more nucleotide pairs are added (insertion) or removed (deletion) to the mRNA.
Why are point mutations considered harmless
Despite a change of a single nucleotide, the chances of the amino acid being changed is small because of the redundancy of mRNA. This means that this type of mutation will change the single nucleotide however the amino acid will remain the same
Why are frameshift mutations considered dangerous
The order of codons are changed after the mutation point, this means that the order of amino acids will change as well. This will result in a different protein being formed or in some cases a non-functional protein
What are the four types of chromosome mutations
Deletion, duplication, inversion and translocation (substitution)
What is non-disjunction
When a homologous pair is unable to separate during meiosis
What chromosomes is non-disjunction most common in
Sex chromosome and chromosome 21
What is a trisomy
Having an extra sex chromosome
What is a monosomy
Having one sex chromosome
What is polyploidy
Having a large number of chromosomes
What is a mutagen
A substance or form of energy that causes a mutation (eg. radiation via UV rays, chemical agents like nicotine and alcohol.
