Chapter 13 – Altering the Genetic Material: Mutation and DNA Repair

Flashcards covering key vocabulary terms related to mutations, their consequences, causes, and DNA repair as discussed in Chapter 13.

Mutation

A heritable change in the genetic material, essential for variation in natural selection.

Point Mutation

A mutation that affects only a single base pair within the DNA sequence.

Base Substitution

A type of point mutation where one base is replaced by another.

DNA Repair Systems

Mechanisms that reverse most DNA damage before a permanent mutation occurs.

Germ-Line Cells

Cells that give rise to gametes (sperm and egg) and can be passed to offspring.

Somatic Cells

All body cells other than germ-line cells; mutations here are not inherited.

Silent Mutation

A point mutation that does not change the amino acid sequence of a polypeptide.

Missense Mutation

A point mutation that results in the substitution of one amino acid for another in a polypeptide.

Nonsense Mutation

A point mutation that creates a premature stop codon in the amino acid sequence.

Frameshift Mutation

A mutation caused by the addition or deletion of base pairs that alters the reading frame of the gene.

Mutagen

An environmental agent that causes mutations in DNA, either chemically or physically.

Ames Test

A test that determines if a substance is a mutagen by monitoring the mutation rate in specific bacteria.

Nucleotide Excision Repair (NER)

The most common DNA repair system that removes damaged regions of DNA.

Thymine Dimers

Structures formed when UV light causes adjacent thymine bases in DNA to bond incorrectly.