Human Cells: Mutations Flashcards
What are mutations?
Changes in DNA that can result in absence of protein or production of an altered protein
What do single gene mutations involve?
The alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides
What do nucleotide substitutions give rise to?
Missense, nonsense and splice-site mutations
Missense mutations result in what?
One amino acid being changed for another. This can give a non-functional protein or have little effect on the protein.
Nonsense mutations result in what?
A premature stop codon being produced, which gives a shorter protein
What do splice-site mutations result in?
Some introns being retained and/or some exons not being included in the mature transcript
Nucleotide insertions and deletions result in what?
Frame-shift mutations
What do frame-shift mutations cause?
All of the codons and all of the amino acids after the mutation to be changed. This has a major effect on the structure of the protein that is produced
What do chromosome structure mutations that involve changes to the structure of a chromosome involve?
Duplication, deletion, inversion and translocation
When does duplication happen?
When a section of a chromosome is repeated
What happens in deletion?
A secretion of chromosome is removed
What happens in inversion?
A section of chromosome is reversed
When does translocation happen?
When a section of a chromosome is added to a chromosome, not its homologous partner
The substantial changes involved in chromosome mutations often make them what?
Lethal
