Molecular basis of mutations — A/L Biology

A. Mutation Definition and Types Definition: A mutation is a permanent alteration in the DNA sequence that makes up a gene, ranging from a single base pair change to large chromosomal rearrangements. Explanation: Mutations are changes in the genetic material that can occur spontaneously or be induced by mutagens. They can be classified into two main types: gene mutations (point mutations affecting single genes) and chromosomal mutations (affecting chromosome structure or number). Gene mutations include substitutions, insertions, and deletions, while chromosomal mutations include duplications, deletions, inversions, and translocations. Mutations can be harmful, beneficial, or neutral depending on their effect on protein function and organism survival. Think of it as: Think of DNA as a recipe book for making proteins. A mutation is like a typo in the recipe - sometimes it changes nothing (like 'teh' instead of 'the'), sometimes it ruins the dish (like 'salt' instead of 'sugar'), and rarely it might improve the recipe.