Mutations Flashcards
mutations that occur in the natural environment
spontaneous mutations
an incorrect base is incorporated into the dNA during replication
base substitutions
only 1 base is changed
point mutation
if a base substitution leads to a substitution of different amino acids in protein
missense mutation
if base substitution creates a stop codon instead of normal AA coding codon
nonsense mutation
removal or addition of nucleotides leads to change in the way DNA sequence is read, that is it changes the codon frame or reading frame
frameshift
segments of DNA that can move spontaneously from one site to another in the same of different DNA molecules
transposons aka jumping genes
a change in DNA sequence that is the result of a mutagen such as radiation or chemical agents
induced mutations
these mutations alter the binding of the DNA molecule
chemical mutagens
3 types of chemical mutagens
alkylating agents, base analogs, intercalating agents
what do alkylating agents do?
highly reactive chemical that add alkyl groups to nitrogenous bases altering their H bonding
What do base analogs do?
comounds that resemble the bases closely enough that they are incorported into DNA in place of natural bases
What are intercalating agents?
planar molecules that wedge of intercalate between pairs of DNA, do not change bonding patterns
what are the 2 types of radiation that cause mutation
- UV and 2. Xray
UV light causes
thymine dimers
