1.4. Genes and Proteins in Health and Disease Flashcards
What is a mutation?
A change in structure or composition of a genome.
What is a single gene mutation?
A mutation resulting from the alteration of one gene.
What is a point mutation?
The change in one nucleotide.
What are the three types of point mutation?
Substitution, Insertion and Deletion.
Describe a substitution mutation.
When one nucleotide is substituted for another and therefore a different amino acid is coded for which makes sense, but not the original sense. This kind of mutation is called a missense mutation.
Describe an insertion and deletion mutation.
When one nucleotide is either put in or taken out of a sequence. This can lead to a frameshift mutation.
What is a frameshift mutation?
When every codon and amino acid coded for is altered from the point of insertion or deletion.
What is a nonsense mutation?
When a substitution mutation causes a stop codon to be coded for instead of the original codon. This halts protein synthesis causing it to be shorter than needed.
What is a chromosome structure mutation?
A mutation on a chromosome that involves the breakage of at least one chromosome. The broken part can join onto another chromosome afterwards.
What are the three types of chromosome structure mutations?
Deletion, Duplication and Translocation.
Describe a deletion chromosome structure mutation.
This is the breakage of a chromosome in two places which detaches a segment of it, the two remaining parts then join up and the segment is free.
Describe a duplication chromosome structure mutation.
When the two deleted genes of another chromosome join another chromosome resulting in some genes being repeated. The deleted genes are from the chromosomes matching partner.
Describe a translocation chromosome structure mutation.
This is when deleted genes from another chromosome that is not its matching pair joins onto another chromosome. Reciprocal translocation is when two chromosomes essentially swap genes and non-reciprocal is when only one chromosome loses its genes.
