Using the table of codons below, determine the DNA sequence which produced the following amino acid strand: Alanine - Methionine - Alanine
Understand the Problem
The question asks to determine the DNA sequence that codes for the amino acid sequence Alanine - Methionine - Alanine, using the provided table of mRNA codons and their corresponding amino acids.
Answer
The answer is G-C-G-A-U-G-G-C-G.
The DNA sequence that would produce the amino acid strand Alanine - Methionine - Alanine is G-C-G-A-U-G-G-C-G, which is option D.
Answer for screen readers
The DNA sequence that would produce the amino acid strand Alanine - Methionine - Alanine is G-C-G-A-U-G-G-C-G, which is option D.
More Information
To determine the DNA sequence, you need to find the mRNA codons for each amino acid and then find the complementary DNA sequence. From the table, Alanine can be coded by GCA, GCC, GCG, or GCU, and Methionine is coded by AUG. Let's pick GCG for Alanine to ensure there is a valid answer amongst the multiple choice. The mRNA sequence is GCG-AUG-GCG. Replacing Uracil (U) with Thymine (T) isn't required because the question asks for the original DNA sequence, not the template DNA sequence. The complementary DNA sequence would be: C-G-C-T-A-C-C-G-C. However, since the question asks for the DNA sequence which codes for the given amino acids and not the template strand, we should use the same sequence as the mRNA but replace U with T: G-C-G-A-U-G-G-C-G.
Tips
A common mistake is confusing the coding strand and the template strand of DNA. The coding strand has the same sequence as the mRNA (with U replaced by T), while the template strand is complementary to the mRNA.
Sources
- DNA and RNA codon tables - Wikipedia - en.wikipedia.org
- The genetic code & codon table (article) - Khan Academy - khanacademy.org
AI-generated content may contain errors. Please verify critical information
