Question

suppose the following mutation occurred in dna.
original sequence: ccc atc
mutated sequence: ccg atc
will this mutation affect the protein resulting from this gene sequence?

yes, the amino acid sequence has been changed
no, mutations in the dna do not affect the mrna sequence
no, the amino acid sequence has not been changed
yes, all mutations change the resulting protein

Explanation:

To determine if the mutation affects the protein, we analyze the DNA codons. The original DNA sequence has "CCC" (codes for Proline) and mutated "CCG" (also codes for Proline, due to genetic code degeneracy). The second codon "ATC" remains unchanged. So the amino acid sequence is not altered. Now, we analyze the options:

• Option 1: Incorrect, as the amino acid sequence is not changed.
• Option 2: Incorrect, DNA mutations can affect mRNA (transcription uses DNA as template).
• Option 3: Correct, as explained, the amino acid sequence is unchanged.
• Option 4: Incorrect, not all mutations change the protein (e.g., silent mutations like this one).

Answer:

C. No, the amino acid sequence has not been changed