genetic information (mutations and diversity) Flashcards
what is a mutation?
change to the base sequence of DNA
what is a substitution?
one base is subsituted for another
what is a deletion?
one base is deleted
what does the order of DNA bases determine?
the order of amino acids in a protein
why do not all mutations affect the order of amino acids?
triplet code is degenerate so more than one triplet codes for more than one amino acid- so subsitutions could still code for the same amino acid
why do deletions always change the amino acid sequence?
deletion of a bases changes the number of bases present, which causes frameshift to occur
what are mutagenic agents?
things that increase the rate of mutations
what are examples of mutagenic agents?
ultraviolet radiation
ionising radiation
some chemicals
some viruses
what is genetic diversity?
the number of different alleles in a species/population
how is genetic diversity increased?
by mutations in DNA which form new alleles
when different alleles are introduced into a population when individuals from another population migrate (gene flow)
what happens in the founder effect?
type of genetic bottleneck where there is only a small number of alleles in the initial gene pool
what happens in a genetic bottleneck?
large number of a population die, which reduces the population, after reproduction there is reduced genetic diversity
what is the purpose of natural selection?
to increase advantageous alleles within a population
what happens during natural selection?
not all individuals in a population are as likely to reproduce
different alleles increase an individual’s chance of survival
greater proportion inherit the beneficial allele
more likely to survive, reproduce and pass on useful genes
what are behavioural adaptations?
ways an organism acts that increase its chance of survival and reproduction
eg) play dead
