Textbook Question
Describe the gene and protein defects in phenylketonuria (PKU). How are these defects connected to disease symptoms?
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 2d
In the experiments that deciphered the genetic code, many different synthetic mRNA sequences were tested.
Predict the results of experiments examining GCUA repeats.
Verified step by step guidance1
Understand the problem: The question involves deciphering the genetic code using synthetic mRNA sequences. The sequence provided is a repeating GCUA. Each codon (group of three nucleotides) in the mRNA sequence corresponds to a specific amino acid based on the genetic code.
Break the repeating sequence into codons: The sequence GCUA repeats, so write it as GCUA GCUA GCUA... and identify the codons. Since codons are groups of three nucleotides, the sequence will produce overlapping codons: GCU, CUA, UAG, and so on.
Determine the amino acids for each codon: Use the genetic code table to find the amino acids corresponding to each codon. For example, GCU codes for Alanine (Ala), CUA codes for Leucine (Leu), and UAG is a stop codon.
Predict the results: The presence of a stop codon (UAG) in the sequence will terminate translation. Therefore, the polypeptide produced will depend on where translation starts and will stop when the ribosome encounters the UAG codon.
Summarize the findings: The repeating GCUA sequence will produce short polypeptides that vary depending on the reading frame. Translation will terminate at the UAG stop codon, and the specific amino acids in the polypeptide will depend on the codons read before the stop codon.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Genetic Code
The genetic code is a set of rules that defines how the sequence of nucleotides in mRNA is translated into amino acids, the building blocks of proteins. It consists of codons, which are triplets of nucleotides, each corresponding to a specific amino acid or a stop signal during protein synthesis. Understanding the genetic code is essential for predicting the outcomes of experiments involving mRNA sequences.
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The Genetic Code
mRNA and Translation
Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to the ribosome, where proteins are synthesized. During translation, ribosomes read the mRNA sequence in codons, facilitating the assembly of amino acids into a polypeptide chain. The specific sequence of mRNA, such as GCUA repeats, will influence the resulting protein's structure and function.
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Repetitive Sequences
Repetitive sequences in mRNA, such as GCUA repeats, can affect the stability and translation efficiency of the mRNA. These sequences may lead to the formation of secondary structures that can hinder or enhance ribosome binding. Understanding how these repeats influence translation is crucial for predicting the results of experiments involving synthetic mRNA.
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Related Practice
Textbook Question
In the experiments that deciphered the genetic code, many different synthetic mRNA sequences were tested.
Describe how the codon for phenylalanine was identified.
Textbook Question
In the experiments that deciphered the genetic code, many different synthetic mRNA sequences were tested.
What was the result of studies of synthetic mRNAs composed exclusively of cytosine?
Textbook Question
In the experiments that deciphered the genetic code, many different synthetic mRNA sequences were tested.
What result was obtained for synthetic mRNAs containing AG repeats, that is, AGAGAGAG...?
Textbook Question
Several lines of experimental evidence pointed to a triplet genetic code. Identify three pieces of information that supported the triplet hypothesis of genetic code structure.
Textbook Question
Outline the events that occur during initiation of translation in E. coli.