Point mutation

Definition

A point mutation is a genetic alteration where a single nucleotide base pair in the DNA sequence is changed. This can result in different types of mutations such as silent, missense, or nonsense mutations.

5 Must Know Facts For Your Next Test

1. Point mutations can be caused by errors during DNA replication or by exposure to mutagens.
2. Missense mutations result from point mutations that change one amino acid in a protein.
3. Nonsense mutations create a premature stop codon, potentially leading to nonfunctional proteins.
4. Silent mutations are point mutations that do not alter the amino acid sequence of the protein.
5. Point mutations can have significant effects on microbial genetics, including antibiotic resistance.

Review Questions

• What is a point mutation and what are its possible consequences?
• How do missense and nonsense mutations differ?
• Why might a silent mutation not affect the function of a protein?

Related terms

Frameshift Mutation:

A genetic alteration caused by insertions or deletions of nucleotides that change the reading frame of the gene.

Mutagen:

An agent, such as radiation or a chemical substance, which causes genetic mutation.

Codon:

A sequence of three nucleotides in mRNA that specifies an amino acid or termination signal during translation.