Third-base wobble allows some tRNAs to recognize more than one mRNA codon. Based on this chapter's discussion of wobble, what is the minimal number of tRNA molecules necessary to recognize the following amino acids?
Isoleucine

Verified step by step guidance

1. Understand the concept of wobble: Wobble refers to the flexibility in base pairing at the third position of the codon, allowing some tRNAs to pair with multiple codons. This reduces the number of tRNAs required to recognize all codons for a given amino acid.
2. Identify the codons for isoleucine: Isoleucine is encoded by three codons in the genetic code: AUU, AUC, and AUA.
3. Analyze the wobble rules: The third position of the codon can pair with multiple bases due to wobble. For example, the anticodon of a tRNA may have inosine (I), which can pair with U, C, or A in the third position of the codon.
4. Determine the minimal number of tRNAs: Based on wobble pairing, a single tRNA with an anticodon containing inosine at the wobble position can recognize AUU, AUC, and AUA. However, some organisms may use more than one tRNA for isoleucine depending on their genetic makeup.
5. Conclude the reasoning: The minimal number of tRNA molecules necessary to recognize the codons for isoleucine is one, assuming wobble pairing is utilized effectively.

Key Concepts

tRNA and Codons

Transfer RNA (tRNA) is a type of RNA molecule that helps decode mRNA sequences into proteins. Each tRNA molecule carries a specific amino acid and has an anticodon that pairs with a corresponding mRNA codon. Understanding the relationship between tRNA and codons is essential for determining how many tRNA molecules are needed to recognize various amino acids.

Wobble Hypothesis

The wobble hypothesis explains how the third position of a codon can tolerate certain mismatches between the codon and anticodon. This flexibility allows a single tRNA to pair with multiple codons that code for the same amino acid, reducing the total number of tRNA molecules required for protein synthesis. Recognizing this concept is crucial for answering questions about the minimal number of tRNAs needed.

Amino Acid Codons

Amino acids are encoded by specific sequences of three nucleotides known as codons. For isoleucine, there are three codons (AUU, AUC, AUA) that specify this amino acid. Understanding the codons associated with isoleucine is necessary to determine how many distinct tRNA molecules are required to recognize all codons for this amino acid, especially considering the wobble effect.