In the experiments that deciphered the genetic code, many different synthetic mRNA sequences were tested.

Describe how the codon for phenylalanine was identified.

Verified step by step guidance

1. span>Step 1: Understand the context of the experiment. The genetic code was deciphered using synthetic mRNA sequences to determine which amino acids correspond to which codons.</span
2. span>Step 2: Recognize the role of Nirenberg and Matthaei's experiment. They used a cell-free system to translate synthetic mRNA into proteins.</span
3. span>Step 3: Identify the specific synthetic mRNA used. In this case, a poly-U mRNA sequence (UUUUU...) was used in the experiment.</span
4. span>Step 4: Analyze the results of the translation. The poly-U mRNA directed the synthesis of a polypeptide consisting entirely of phenylalanine.</span
5. span>Step 5: Conclude the identification process. The experiment demonstrated that the codon UUU codes for the amino acid phenylalanine.</span

Key Concepts

Codons

Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids or stop signals during protein synthesis. Each codon is crucial for translating the genetic information encoded in DNA into functional proteins. Understanding codons is essential for deciphering how genetic information is expressed and how specific amino acids, like phenylalanine, are incorporated into proteins.

Synthetic mRNA

Synthetic mRNA refers to artificially created messenger RNA sequences used in experiments to study the genetic code. By introducing these synthetic mRNA sequences into a system, researchers can observe which amino acids are produced, allowing them to identify the corresponding codons. This method was pivotal in determining the specific codon that codes for phenylalanine.

Amino Acid Translation

Amino acid translation is the process by which the sequence of codons in mRNA is translated into a sequence of amino acids, forming a protein. This process occurs during translation, where ribosomes read the mRNA and tRNA molecules bring the appropriate amino acids. Identifying the codon for phenylalanine involved determining which specific codon sequence led to the incorporation of phenylalanine during this translation process.