Lecture 15 Review: DNA Mutations and Repair Mechanisms

These flashcards cover key vocabulary terms related to DNA mutations and repair mechanisms for the upcoming exam.

Mutation

Heritable changes in the DNA sequence that can result from errors in DNA replication or environmental factors.

Germline mutation

A mutation occurring in gamete-producing cells that is heritable and passed to progeny.

Somatic mutation

A mutation occurring in body cells that is not passed on to offspring.

Base substitution

A mutation involving the replacement of one nucleotide with another, resulting in point mutations.

Frameshift mutation

A mutation caused by insertion or deletion of nucleotides that shifts the reading frame of the genetic code.

Ames Test

A test used to assess the mutagenic potential of compounds by observing their ability to revert mutant bacteria to wild-type.

Loss-of-function mutation

A mutation that results in the absence or reduced function of a normal protein.

Gain-of-function mutation

A mutation that leads to the appearance of a new trait or the increased activity of a gene product.

Suppressor mutation

A mutation that counteracts the effects of another mutation, restoring function.

Nonsense mutation

A point mutation that changes a codon to a stop codon, resulting in premature termination of translation.

Silent mutation

A mutation that does not change the amino acid sequence of a protein, hence no effect on phenotype.

Chemical mutagens

Agents that cause mutations by altering the chemical structure of DNA.

DNA repair mechanisms

Processes that correct damage to the DNA molecule, including excision repair and mismatch repair.

Indel

Insertion or deletion of nucleotides in a DNA sequence, which can lead to shifts in the reading frame.

Expanding nucleotide repeats

A form of mutation where repeated copies of a short DNA sequence increase in number, often linked to genetic disorders.

Conditional mutation

A mutation that has an effect only under specific environmental conditions.

Mismatched repair (MMR)

A repair mechanism that corrects mismatches in the DNA sequence after replication.

Base excision repair

A DNA repair process that removes damaged bases and replaces them.

Nucleotide excision repair

A universal repair mechanism that removes bulky DNA lesions that distort the double helix.