What are the types of gene mutations?

What are the types of gene mutations?

• A. Substitution, Insertion, Deletion, Silent, Missense, Frameshift, Nonsense
• B. Duplication, Deletion, Inversion, Translocation
• C. Mitosis, Meiosis, Replication, Translation
• D. Gene splicing, Transcription, Translation, Degradation

Answer: (A)

Understanding mutations at the gene level starts with the idea that a single change in DNA can alter a gene’s message. The main categories are substitutions, insertions, and deletions. Substitution means one base is swapped for another, and its effects vary: a silent mutation changes the DNA but not the amino acid, a missense mutation changes one amino acid, and a nonsense mutation creates a premature stop codon, truncating the protein. Insertions add extra bases, while deletions remove bases. If these changes aren’t in multiples of three, the reading frame shifts, so every downstream codon changes — a frameshift mutation that usually wrecks the protein. If the insertion or deletion is in multiples of three, the reading frame stays intact but adds or removes amino acids in the protein sequence. The other options describe larger-scale chromosomal changes or unrelated cellular processes, not the specific ways a gene’s sequence can mutate. Chromosomal changes like duplications, inversions, deletions, and translocations involve bigger DNA segments. The remaining items refer to processes such as cell division, DNA replication, or transcription and translation, not mutation types.

Understanding mutations at the gene level starts with the idea that a single change in DNA can alter a gene’s message. The main categories are substitutions, insertions, and deletions. Substitution means one base is swapped for another, and its effects vary: a silent mutation changes the DNA but not the amino acid, a missense mutation changes one amino acid, and a nonsense mutation creates a premature stop codon, truncating the protein. Insertions add extra bases, while deletions remove bases. If these changes aren’t in multiples of three, the reading frame shifts, so every downstream codon changes — a frameshift mutation that usually wrecks the protein. If the insertion or deletion is in multiples of three, the reading frame stays intact but adds or removes amino acids in the protein sequence.

The other options describe larger-scale chromosomal changes or unrelated cellular processes, not the specific ways a gene’s sequence can mutate. Chromosomal changes like duplications, inversions, deletions, and translocations involve bigger DNA segments. The remaining items refer to processes such as cell division, DNA replication, or transcription and translation, not mutation types.