Meiosis & Mutation Flashcards
what is a mutation?
a change in the DNA base sequence
how does a mutation arise?
spontaneously
what is a substitution mutation?
one base is swapped with a different base in the DNA base sequence
what is a deletion mutation?
one base is removed from the DNA base sequence causing frame shift
what are the possible effects of a substitution mutation on a protein?
the amino acid sequence may be changed which will change the tertiary structure and the function of the polypeptide
what are the possible effects of a deletion mutation on a protein?
the alteration of the base triplets from the mutation onwards changing the amino acid code
what are the 4 types of mutagenic aids?
uv radiation
ionising radiation
carcinogens
chemicals
what does haploid mean?
cells containing 1 of each type of chromosome (23)
what is an example of a haploid cell?
gametes
sperm cell
egg cell
what does diploid mean?
cells containing 2 types of each chromosome as pairs
what is an example of a diploid cell?
normal body cell
what are homologous chromosomes?
one chromosome of each pair is from the mother and the other is from the father
what is crossing over?
the homologous chromosomes come together as a pair forming a bivalent so non-sister chromatids are paired together
how does crossing over result in genetic variation?
resulting chromatids contain the same genes but different alleles
what is independent segregation?
homologous chromosomes line up along the equator of the cell randomly
