U1KA4 Flashcards
What are mutations?
They are spontaneous (random) changes in the DNA.
What do mutations result in?
no protein or an altered protein being synthesised.
What are the three types of single gene mutations?
insertion, deletion and substitution.
What are the results of single gene mutations?
the alteration of a DNA nucleotide sequence in one gene, resulting a mistake being made during DNA replication.
What is insertion in single gene mutation?
an extra nucleotide being added.
What is deletion in single gene mutation?
a nucleotide being delete or missed out.
What does insertion and deletion cause?
frame-shift mutations
What are frame-shift mutations?
When all of the codons and all of the amino acids after the mutation being changed, therefore the protein created being different.
What is substitution in single gene mutation?
when one nucleotide is swapped for another.
What is the effectof nucleotide change?
causes a change in the order of amino acids produced in the protein and may then affect the structure of the protein.
What are the 2 different affects in the DNA code called?
missense and nonsense mutations.
What is missense mutation in single gene mutations?
where one amino acid is replaced with another
What is nonsense mutation in single gene mutation?
when a stop codon is produced early in an mRNA chain leading to a short protein.
What happens in splice site mutations?
either introns being retained or some exons not being included in the mature transcript
What does splice site mutation cause?
incorrect amino acids being joined together in the ribosome.
