What is a change in a gene or chromosome?

• A. Nitrogen base
• B. 5-carbon sugar
• C. Mutation
• D. Amino acid

Answer: (C)

A change in genetic material is called a mutation. Mutations are alterations to the DNA sequence or to chromosome structure that can change how a gene functions. They can be small, like a base substitution, insertion, or deletion in DNA, or larger, such as deletions, duplications, or rearrangements of chromosome segments. Because these changes modify the genetic code, they can affect the amino acid sequence of a protein or how a gene is regulated, leading to different traits or phenotypes. Nitrogen bases and the 5-carbon sugar are components of DNA, not changes themselves, and an amino acid is a building block of proteins that can be affected by a mutation but is not a change in genetic material on its own. Mutations can be neutral, beneficial, or harmful and can be passed on if they occur in germ cells.