Question

Which of the following codons codes for the amino acid phenylalanine?

• A. AUG.
• B. UUU.
• C. GCA.
• D. CCC.

Hint:

Memorize the key codons like AUG (start codon) and those coding for frequently asked amino acids, such as UUU/UUC for phenylalanine.

Answer 1

The Correct Option is B

Step 1: Understanding the genetic code.
The genetic code is a set of rules by which nucleotide sequences in mRNA are translated into amino acids. Each codon (a sequence of three nucleotides) corresponds to a specific amino acid. Step 2: Codon for phenylalanine.
The codons that code for the amino acid phenylalanine (\(Phe\)) are: \[ \text{UUU and UUC}. \] Among the given options, \(UUU\) is the correct codon for phenylalanine. Step 3: Explanation of other options.
Option (A): AUG. Incorrect. AUG is the start codon and codes for methionine. Option (B): UUU. Correct. UUU codes for phenylalanine. Option (C): GCA. Incorrect. GCA codes for alanine. Option (D): CCC. Incorrect. CCC codes for proline. Step 4: Conclusion.
The correct codon for phenylalanine is \(UUU\). \[ \therefore \text{The correct answer is: (B)}. \]