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Ch. 9 - The Molecular Biology of Translation
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
All textbooksSanders 3rd EditionCh. 9 - The Molecular Biology of TranslationProblem 13a
Chapter 9, Problem 13a

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?
Leucine

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 a single tRNA to recognize multiple codons. This is due to non-standard base pairing rules at the third position.
Identify the codons for leucine: Leucine is encoded by six codons in the genetic code: UUA, UUG, CUU, CUC, CUA, and CUG.
Group the codons based on wobble compatibility: The codons can be grouped based on their third-base wobble pairing. For example, UUA and UUG can be recognized by one tRNA, while CUU, CUC, CUA, and CUG can be recognized by another tRNA.
Determine the minimal number of tRNAs: Analyze the wobble rules and groupings to determine how many distinct tRNAs are required to recognize all six codons for leucine. Consider the base pairing flexibility at the third position.
Conclude the minimal number of tRNAs: Based on the grouping and wobble rules, calculate the minimal number of tRNAs necessary to recognize all leucine codons without specifying the final number.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Wobble Hypothesis

The wobble hypothesis explains how the third position of a codon can pair with multiple tRNA anticodons, allowing a single tRNA to recognize more than one codon. This flexibility in base pairing is crucial for efficient protein synthesis, as it reduces the number of tRNA molecules needed to translate the genetic code.
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Translation:Wobble Hypothesis

Codons and Amino Acids

Codons are sequences of three nucleotides in mRNA that specify particular amino acids during protein synthesis. Each amino acid can be encoded by multiple codons, which is particularly true for leucine, which has six different codons. Understanding the relationship between codons and their corresponding amino acids is essential for determining the number of tRNAs required.
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tRNA

tRNA Molecules

Transfer RNA (tRNA) molecules are responsible for bringing the appropriate amino acids to the ribosome during translation. Each tRNA is specific to one amino acid and can recognize one or more codons due to the wobble effect. The number of distinct tRNA molecules needed depends on the number of unique codons for a given amino acid, factoring in wobble pairing.
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Related Practice
Textbook Question

If you were to look up Gaucher disease on the OMIM website, you would see that there are three major types, designated Type I (OMIM 230800), Type II (OMIM 230900), and Type III (OMIM 231000). All three types are mutations of the gene for acid-β-glucosidase, encoded on chromosome 1. Different mutations of this gene produce the three types of Gaucher disease that differ somewhat in their symptoms and disease severity.

For each mutation, speculate about whether the acid-β-glucosidase enzyme is merely reduced in function or whether its production is eliminated, and explain why.

Textbook Question

The diagram of a eukaryotic ribosome shown below contains several errors.

Examine the diagram carefully, and identify each error.

Textbook Question

The diagram of a eukaryotic ribosome shown below contains several errors.

Redraw the diagram, and correct each error using the mRNA sequence shown.

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Textbook Question

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?

Arginine

Textbook Question

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

Textbook Question

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?

Lysine