Which of the following describes a large-scale mutation affecting chromosome structure?

• A. Point mutation
• B. Chromosomal mutation
• C. Gene mutation
• D. Translocation

Answer: (B)

A large-scale mutation affecting chromosome structure is best described as a chromosomal mutation. These mutations involve changes to the structure or number of entire chromosomes, which can include deletions, duplications, inversions, or translocations of chromosomal segments.

In contrast, a point mutation specifically refers to a change in a single nucleotide base pair within a gene, which does not affect the overall chromosome structure but rather the specific sequence of DNA. Gene mutations also pertain to changes within a gene's sequence without implicating larger chromosomal alterations. Translocation, while it can involve changes in chromosome structure, specifically refers to the movement of a segment from one chromosome to another and is considered a subtype of chromosomal mutation rather than a broad category.

Therefore, the broadest and most inclusive term for large-scale mutations affecting chromosome structure is chromosomal mutation.