Mutations

Definition

Mutations are changes in the nucleotide sequence of DNA, which can occur spontaneously or due to environmental factors. They can result in alterations to gene function and affect an organism's phenotype.

5 Must Know Facts For Your Next Test

1. Mutations can be categorized as point mutations, insertions, deletions, and chromosomal rearrangements.
2. The three main types of point mutations are silent, missense, and nonsense mutations.
3. Mutations can be caused by errors during DNA replication or by external factors like UV radiation and chemical exposure.
4. DNA repair mechanisms, such as nucleotide excision repair and mismatch repair, help correct mutations.
5. Some mutations are beneficial and contribute to genetic diversity and evolution.

Review Questions

• What are the different types of point mutations?
• How do external factors contribute to the occurrence of mutations?
• What role do DNA repair mechanisms play in relation to mutations?

Related terms

Nucleotide Excision Repair: A DNA repair mechanism that removes bulky lesions from the DNA structure.

Missense Mutation: A type of point mutation where a single nucleotide change results in a codon that codes for a different amino acid.

Chromosomal Rearrangement: Structural changes in chromosomes involving large segments of DNA being moved or reoriented.