4B - Mutations Flashcards
What are the 3 types of mutation?
Chromosomal, deletion and substitution.
What is a deletion mutation?
One base is deleted from the sequence.
What is a substitution mutation?
One base is substituted with another in a sequence.
Which is worse, a deletion or substitution mutation?
A deletion.
What effect can a deletion mutation have on the order of the bases?
Shifts the base triplets to the left so the whole amino acid sequence changes.
What effect can a substitution mutation have on the order of the bases?
Only affects the base in which the substitution is made and doesn’t alter the rest of the sequence of amino acids.
What are mutagenic agents/what do they do?
Things that cause an increase in the rate of mutations.
What are examples of mutagenic agents?
UV radiation, ionising radiation, some chemicals and some viruses.
What is cross fertilisation?
The fusion of male and female gametes.
How do you work out the number of possible combinations of chromosomes there will be in humans?
2^n
Where n is the haploid number.
What produces/doesn’t produce genetic novelty?
Mutations produce it but genetic variation does not.
What are chromosomal mutations?
Changes in whole set of chromosomes,
Or,
Changes in number of individual chromosomes.
What is a mutation?
Any change to the quantity or the base sequence of the DNA of an organism.
What might mutated alleles lead to?
Loss of function of a gene and so be harmful.
Are mutations always bad?
Why?
They increase genetic diversity - so no.
They may lead to loss of function of a gene and so may be harmful - so yes.
They might be more useful/beneficial to the organism - so no.
