Chapter 19 - Cells Flashcards
What types of mutations are there?
Substitution
Insertion
Deletion
What is substitution?
When one nucleotide is exchanged for another
What is insertion?
When an extra nucleotide (or more than one) is placed in the DNA sequence
What is deletion?
When a nucleotide (or more than one) is removed from the DNA sequence
Which genetic disease is caused by substitution?
Sickle cell anaemia
Which genetic disease is caused by insertion?
Huntington’s disease
Which genetic disease is caused by deletion?
Cystic fibrosis
What is a mutation?
A change to the base sequence
What is a frameshift mutation?
An insertion or deletion mutation which therefore causes the change of subsequent codons
Each following codon is effected because they are read in a new group of threes
What is a silent mutation?
A mutation that changes the primary structure of the protein (base sequence) but had no significant effect in its function
How does a silent mutation occur?
The mutation could be in a non-coding region
The mutation could produce a new codon that codes for the same amino acid ( because DNA code is degenerate)
What is a nonsense mutation?
A codon that is changed to a stop codon
This results in a shorter polypeptide and is normally harmful
What is a missense mutation?
When at least one new amino acid is introduced into the protein’s primary
Can be harmful or beneficial
