Topic 4B Flashcards
Genetic Diversity (12 cards)
What is a gene mutation?
A change in the DNA base sequence.
When do most gene mutations take place?
Most happen spontaneously during the process of DNA replication.
What are mutagens?
Factors that increase the rate of mutations such as ultraviolet and ionising radiation, chemicals, and viruses.
What is a substitution mutation?
When one base in replaced by another in a DNA sequence.
What is a deletion mutation?
When one base is removed from a DNA sequence. This causes a frameshift.
What is an insertion mutation?
When one base is added into a DNA sequence.
Why do many substitution mutations have no effect on protein structure?
The genetic code is degenerate. This means that substitutions often result in the same amino acid being coded for. There is also no frameshift.
Why are deletion mutations likely to change protein structure?
They cause a frame shift to the left which changes the amino acid sequence.
What is a frameshift?
When the entire DNA base sequence after a mutation is shifted either to the left or the right.
Why are insertion mutations likely to affect protein structure?
They cause a frameshift to the right which changes the amino acid sequence.
What is a chromosome mutation?
A change in the structure or number of chromosomes.
