14.1: How Does Mutation Arise

mutations

are changes in the nucleotide sequence of an organism's DNA, which can lead to alterations in genes and potentially affect an organism's traits.

allele

variant forms of a gene

genotype

genetic makeup of an individual, representing the specific allele combinations inherited from parents.

phenotype

the observable characteristics determined by its genotype.

spontaneous mutations

occur without outside influence

induced mutation

occur when mutagen from outside of cell changes DNA leading to mutation

• certain chemicals can alter nucleotide bases

• radiation can block DNA replication

somatic mutations

occurs in somatic cells and passed on to daughter cells during mitosis but not passed onto sexually produced offspring

germ line mutations

occurs in germ line cells which give rise to gametes and is passed to offspring at fertilisation and offspring will have mutation in every cell

2 types of mutations that affects phenotypes

loss of function and gain of function

benefits of double stranded helix in terms of mutations

2 separate copies of genetic information = when one strand is damaged the complementary strand can be used as a template to restore the correct nucleotide sequence

how can mutations be beneficial

provide genetic diversity making natural selection possible = causes phenotype to be more advantageous if environment changes