Mutations

--> types of gene mutations and their possible effects on protein production and dunction, including substitution, insertion or deletion of one or more nucleotides AND the possible effects of these gene mutations (i.e. beneficial, neutral or harmful).

mutation - a change to the amount of or arrangement of genetic material in a cell

-mutations generally occur when DNA is copied in the S phase of interphase

-mutations can only be inherited if the mutation occurs in the germ cells (those producing gametes)

-certain mutagens (environmental factors) can increase the rate of mutation; ionising radiation such as alpha radiation, UV radiation, and chemicals such as benzene

-there are two types of mutation;

• chromosome mutations
• DNA mutations

chromosome mutations

-attributed to non-disjunction, i.e. chromosome 21 failing to separate during meiosis so an egg cell receives two copies of this chromosome, so fertilisation would result in a zygote with three copies of chromosome 21. the resulting condition is known as…