If a base-pair change occurs in DNA, thisa. is a mutation.b. would be a mutation only if it falls in a protein-coding part of a gene.c. would be a mutation only if it falls in a transcribed part of the genome.d. is not a mutation, because only one base pair has been altered.

Verified step by step guidance

1. Understand the definition of a mutation: A mutation is any change that occurs in the sequence of DNA, regardless of its location or the number of base pairs involved.
2. Consider the impact of a single base-pair change: Even a change in just one base pair can affect the DNA sequence and potentially alter the function of a gene or its regulatory elements.
3. Evaluate the options given in the question: Analyze each option to determine if it aligns with the definition and characteristics of a mutation.
4. Identify the correct option: Choose the option that correctly states that any base-pair change in DNA, regardless of its location or effect, is considered a mutation.
5. Eliminate incorrect options: Options that specify the mutation must occur in specific parts of the DNA or suggest that a single base-pair change is not a mutation do not align with the broad definition of a mutation.

Key Concepts

Mutation

A mutation is a permanent alteration in the DNA sequence that makes up a gene. Mutations can occur due to various factors, including environmental influences or errors during DNA replication. They can affect a single base pair or larger segments of DNA, and their consequences can range from benign to significant, potentially leading to diseases or changes in traits.

Protein-Coding Genes

Protein-coding genes are segments of DNA that contain the instructions for synthesizing proteins. These genes are transcribed into messenger RNA (mRNA), which is then translated into a specific protein. Mutations in protein-coding regions can lead to changes in the amino acid sequence of proteins, potentially altering their function and impacting the organism's phenotype.

Transcription and Transcribed Regions

Transcription is the process by which the information in a gene's DNA is copied into mRNA. Transcribed regions include not only protein-coding sequences but also non-coding regions that may play regulatory roles. Mutations in these areas can influence gene expression and the overall function of the genome, even if they do not directly alter protein sequences.