Textbook Question
An experiment by Khorana and his colleagues translated a synthetic mRNA containing repeats of the trinucelotide UUG.
How does the result of this experiment help confirm the triplet nature of the genetic code?
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Ch. 9 - The Molecular Biology of Translation
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
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Table of contents
- Ch. 1 - The Molecular Basis of Heredity, Variation, and Evolution64
- Ch. 2 - Transmission Genetics144
- Ch. 3 - Cell Division and Chromosome Heredity81
- Ch. 4 - Gene Interaction87
- Ch. 5 - Genetic Linkage and Mapping in Eukaryotes103
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages73
- Ch. 7 - DNA Structure and Replication71
- Ch. 8 - Molecular Biology of Transcription and RNA Processing79
- Ch. 9 - The Molecular Biology of Translation110
- Ch. 10 - Eukaryotic Chromosome Abnormalities and Molecular Organization100
- Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination86
- Ch. 12 - Regulation of Gene Expression in Bacteria and Bacteriophage90
- Ch. 13 - Regulation of Gene Expression in Eukaryotes38
- Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics72
- Ch. 15 - Recombinant DNA Technology and Its Applications69
- Ch. 16 - Genomics: Genetics from a Whole-Genome Perspective49
- Ch. 17 - Organelle Inheritance and the Evolution of Organelle Genomes27
- Ch. 18 - Developmental Genetics43
- Ch. 19 - Genetic Analysis of Quantitative Traits66
- Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels105
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
Chapter 9, Problem 28
The following figure contains several examples of the Shine–Dalgarno sequence. Using the seven Shine–Dalgarno sequences from E. coli, determine the consensus sequence and describe its location relative to the start codon.
Verified step by step guidance1
Step 1: Understand the Shine–Dalgarno sequence as a ribosomal binding site in prokaryotic mRNA, typically located upstream of the start codon, which helps initiate translation by aligning the ribosome with the start codon.
Step 2: Collect the seven Shine–Dalgarno sequences from the given E. coli examples and align them to identify conserved nucleotides across all sequences.
Step 3: For each position in the aligned sequences, determine the most frequently occurring nucleotide to establish the consensus sequence. This can be done by creating a position weight matrix or simply noting the dominant base at each position.
Step 4: Note the typical location of the Shine–Dalgarno sequence relative to the start codon, which is usually about 5 to 10 nucleotides upstream (5' direction) of the AUG start codon.
Step 5: Summarize the consensus sequence and describe its position relative to the start codon, emphasizing its role in facilitating ribosome binding and translation initiation.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Shine–Dalgarno Sequence
The Shine–Dalgarno sequence is a short, conserved ribosomal binding site in bacterial mRNA, typically located upstream of the start codon. It helps recruit the ribosome to initiate translation by base-pairing with a complementary sequence in the 16S rRNA of the small ribosomal subunit.
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08:41
Sequencing Difficulties
Consensus Sequence
A consensus sequence represents the most common nucleotides found at each position in a set of similar sequences. It summarizes conserved features and is used to identify functional motifs, such as the Shine–Dalgarno sequence, by highlighting the typical nucleotide pattern.
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08:55Sequencing Overview
Relative Position to the Start Codon
The Shine–Dalgarno sequence is located a few nucleotides upstream (usually 5-10 bases) of the start codon (AUG). This precise positioning is critical for proper alignment of the ribosome with the start codon to ensure accurate initiation of protein synthesis.
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07:Positional Cloning
Related Practice
Textbook Question
The human β-globin polypeptide contains 146 amino acids. How many mRNA nucleotides are required to encode this polypeptide?
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Textbook Question
The mature mRNA transcribed from the human β-globin gene is considerably longer than the sequence needed to encode the 146–amino acid polypeptide. Give the names of three sequences located on the mature β-globin mRNA but not translated.
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Textbook Question
A research scientist is interested in producing human insulin in the bacterial species E. coli. Will the genetic code allow the production of human proteins from bacterial cells? Explain why or why not.
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Textbook Question
Explain why it is not feasible to insert the entire human insulin gene into E. coli and anticipate the production of insulin.
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Textbook Question
Recombinant human insulin (made by inserting human DNA encoding insulin into E. coli) is one of the most widely used recombinant pharmaceutical products in the world. What segments of the human insulin gene are used to create recombinant bacteria that produce human insulin?
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