Mutations and Gene Mutations

These flashcards cover terminology and definitions related to mutations and types of gene mutations as outlined in the provided lecture notes.

Mutation

A change in the nucleotide-base sequence of a gene or DNA molecule.

Germ-cell mutation

Occurs in an organism’s gametes, does not affect the organism itself but does affect its offspring.

Somatic-cell mutation

Occurs in an organism’s body cells and does affect the organism.

Lethal mutation

Causes death, often before birth.

Chromosome mutation

Changes the structure of a chromosome or the loss or gain of a chromosome.

Gene mutation

Mutations that occur on a gene within DNA.

Deletion (chromosome mutation)

A piece of chromosome is deleted.

Duplication (chromosome mutation)

A piece of chromosome is duplicated.

Inversion (chromosome mutation)

A piece of chromosome breaks off, flips around backwards, and reattaches.

Translocation (chromosome mutation)

A piece of chromosome breaks off and reattaches to a nonhomologous chromosome.

Nondisjunction

A chromosome fails to separate during meiosis, resulting in one gamete with an extra chromosome.

Point mutation

The substitution, addition, or removal of a single nucleotide.

Substitution mutation

One nucleotide replaces another, can cause a change of one amino acid.

Silent mutation

A mutation that changes a codon but still codes for the same amino acid.

Missense mutation

A mutation that changes a codon and results in a different amino acid.

Nonsense mutation

A mutation that changes a codon into a stop codon, stopping translation early.

Frameshift mutation

Results in the misreading of the code during translation due to insertion or deletion.

Insertion (frameshift)

One or more nucleotides are inserted, causing a grouping error in remaining codons.

Deletion (frameshift)

One or more nucleotides are deleted, causing a grouping error in remaining codons.