Lecture 19: DNA Mutation and Repair

Vocabulary flashcards covering key concepts of DNA mutation, point mutations, chromosomal alterations, mutagens, and DNA repair mechanisms from Lecture 19.

Mutation

A change in the genetic material of a cell or virus.

Genetic Disorder

A condition that occurs if a mutation has an adverse effect on the phenotype of an organism and is capable of being passed on from one generation to the next.

Point Mutation

A mutation or chemical change occurring in just one base pair of a gene.

Nucleotide-Pair Substitution

A point mutation that replaces one nucleotide and its partner with another pair of nucleotides.

Silent Mutation

A mutation that has no effect on the amino acid produced by a codon because of redundancy in the genetic code.

Nonsense Mutation

A mutation that changes an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein.

Missense Mutation

A mutation that still codes for an amino acid, but not the correct amino acid.

Conservative Mutation

A missense mutation that results in an amino acid change where the properties of the amino acid remain the same.

Non-Conservative Mutation

A missense mutation that results in an amino acid change that has different properties than the wild type.

Frameshift Mutation

A mutation caused by the insertion or deletion of nucleotides that alters the reading frame of a gene.

Chromosomal Alterations

Mutations that change chromosome structure, occurring when a section of a chromosome breaks off and rejoins incorrectly or does not rejoin at all.

Chromosomal Deletion

A mutation that occurs when a chromosome breaks and some genetic material is lost.

Chromosomal Duplication

A mutation in which extra copies of a chromosomal region are formed, altering gene dosage and potentially leading to excess proteins.

Chromosomal Inversion

A chromosomal mutation where two breaks occur in one chromosome and the region between the breaks rotates 180 degrees before rejoining, without changing the overall amount of genetic material.

Chromosomal Insertion

A mutation where material from one chromosome is inserted into another nonhomologous chromosome, potentially disrupting the coding sequence.

Chromosomal Translocation

A mutation where a segment from one chromosome is transferred to a nonhomologous chromosome or to a new site on the same chromosome.

Reciprocal Translocations

Translocations that involve the exchange of segments between two nonhomologous chromosomes.

Spontaneous Mutations

Mutations that can occur during DNA replication, recombination, or repair.

Mutagens

Physical, chemical, or biological agents that can cause mutations.

Proofreading

The activity of DNA polymerases using 3' to 5' exonuclease activity to check newly made DNA and replace any incorrect nucleotides.

Mismatch Repair

A post-replicative DNA repair mechanism in which repair enzymes correct errors in base pairing.

Nucleotide Excision Repair

A DNA repair mechanism in which a nuclease cuts out and replaces damaged stretches of DNA.