Does a DNA mutation always change the protein? Why or why not?

• A. Yes, because every mutation alters the amino acid sequence.
• B. No, because some mutations are silent and do not change the amino acid sequence.
• C. No, because mutations only occur in non-coding regions of DNA.
• D. Yes, because all mutations lead to a change in protein function.

Answer: (B)

Verified step by step guidance

1. Understand that a mutation is a change in the DNA sequence. Mutations can occur in different regions of the DNA, including coding and non-coding regions.
2. Recognize that the genetic code is redundant, meaning that multiple codons can code for the same amino acid. This redundancy can lead to silent mutations, where a change in the DNA sequence does not alter the amino acid sequence of the protein.
3. Identify that mutations can be classified into different types: silent, missense, nonsense, and frameshift. Silent mutations do not change the amino acid sequence, while missense mutations result in a different amino acid, nonsense mutations create a stop codon, and frameshift mutations alter the reading frame.
4. Consider the location of the mutation. Mutations in non-coding regions may not affect the protein directly, as these regions do not code for amino acids. However, they can affect gene regulation and expression.
5. Conclude that not all mutations lead to a change in the protein. Silent mutations and mutations in non-coding regions may not alter the protein's amino acid sequence or function, while other mutations can have significant effects.