DNA Repair and Mutations

Flashcards summarizing key terms and definitions related to DNA repair and mutations.

Point Mutations

These are changes in a single nucleotide base pair in the DNA.

Missense Mutation

A mutation where a change in a single base pair results in the substitution of one amino acid for another in the resulting protein.

Nonsense Mutation

A mutation that results in a premature stop codon, truncating the protein.

Silent Mutation

A mutation that results in no change to the protein's amino acid sequence.

Insertion Mutation

A mutation involving the addition of one or more nucleotide base pairs into a DNA sequence.

Deletion Mutation

A mutation in which one or more nucleotide base pairs are removed from a DNA sequence.

Tautomerism

A phenomenon where nucleotides can exist in different structural forms, leading to errors during DNA replication.

Depurination

A spontaneous mutation involving the loss of a purine base (adenine or guanine) from the DNA.

Deamination

A spontaneous mutation where an amino group is removed from a cytosine, converting it to uracil.

DNA Methylation

A biochemical process that adds a methyl group to DNA, often marking the strand for repair mechanisms.

Alkylation

A chemical modification of DNA where alkyl groups are added, often leading to mispairing during replication.

Nucleotide Excision Repair

A DNA repair mechanism that removes damaged sections of DNA to repair mutations.

Homologous Recombination

A type of genetic recombination that occurs during DNA repair where genetic material is exchanged between homologous DNA sequences.

Thymine Dimers

Damaged DNA structures formed when two adjacent thymine bases bond together due to ultraviolet light exposure.

Chemical Mutagens

Substances that can cause mutations in DNA upon exposure, typically through reaction with DNA components.

Double-Strand Break Repair

A critical DNA repair process that fixes breaks in both strands of the DNA molecule.

Replication Error Rate

The frequency of errors made during the DNA replication process, typically quantified by the number of mistakes per nucleotide copied.