C12 Gene Mutation & DNA Repair

mutation

heritable changes in the genetic material that provide the raw material for evolution.

mutagens

All cells on Earth are exposed to a plethora of agents called ________.

alkylating agents

Mustard gases are ________ - donate an alkyl group to amino or keto groups in nucleotides.

Purines

________ and pyrimidines can exist in tautomeric forms.

spontaneous mutations

changes in the nucleotide of genes that appear to occur naturally.

depurination

- loss of purine bases (adenine or guanine)
- ~10,000 purine bases/cell/day lost

alkylating agents

donate an alkyl group to amino or keto groups in nucleotides

induced mutations

caused by exogenous factors/mutagens

result of either naturally or artificial agents

induced mutations

mistakes during replication

DNA polymerases insert incorrect nucleotides during replication which can lead to mutations

point mutations

replication errors due to mispairing predominantly

tautomers

increase chance of mispairing during DNA replication

tautomeric shifts

differ by only a single proton shift in the molecule

may lead to permanent base-pair changes and mutations

tautomeric shifts

deamination

removal of amine group (adenine or cytosine)

transposons other name

jumping gene

can move within , or between chromosomes, inserting themselves into various location within the genomes

transposons

transposons insert into regulatory region

disrupt proper expression of the gene

effects of transposons

double-stranded breaks, inversions, and translocations

transposon into coding region

alter the reading frame or introduce stop codon