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?
Ch. 9 - The Molecular Biology of Translation
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
Not the one you use?Change textbookSelect a different textbook
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 25a
An experiment by Khorana and his colleagues translated a synthetic mRNA containing repeats of the trinucelotide UUG.
How many reading frames are possible in this mRNA?
Verified step by step guidance1
Understand the concept of a reading frame: A reading frame is a way of dividing a sequence of nucleotides in mRNA into consecutive, non-overlapping triplets (codons). Each codon specifies an amino acid during translation.
Recognize that mRNA is read in the 5' to 3' direction, and the reading frame depends on where translation starts. For a given sequence, there are three possible reading frames, depending on whether translation starts at the first, second, or third nucleotide.
Analyze the given mRNA sequence: The synthetic mRNA contains repeats of the trinucleotide UUG. This means the sequence is something like UUGUUGUUG... and so on.
Determine the reading frames: Starting at the first nucleotide (U), the first reading frame would be UUG, UUG, UUG... Starting at the second nucleotide (U), the second reading frame would be UGU, UGU, UGU... Starting at the third nucleotide (G), the third reading frame would be GUU, GUU, GUU...
Conclude that there are three possible reading frames in this mRNA sequence, as is the case for any mRNA sequence, regardless of its specific nucleotide composition.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Reading Frames
A reading frame refers to the way nucleotides in mRNA are grouped into codons, which are sets of three nucleotides that correspond to specific amino acids. Since mRNA can be read in three different ways depending on where the reading starts, each starting point creates a different reading frame. This is crucial for understanding how genetic information is translated into proteins.
Recommended video:
Guided course
11:43
The Genetic Code
Codons
Codons are sequences of three nucleotides in mRNA that specify a particular amino acid during protein synthesis. The genetic code consists of 64 possible codons, which include 61 that code for amino acids and 3 that serve as stop signals. Understanding codons is essential for interpreting how sequences of mRNA translate into functional proteins.
Recommended video:
Guided course
11:43The Genetic Code
Synthetic mRNA
Synthetic mRNA is artificially created RNA that can be designed to contain specific sequences of nucleotides. In the context of experiments, synthetic mRNA allows researchers to study the translation process and the effects of specific nucleotide sequences on protein synthesis. This is particularly relevant in experiments like those conducted by Khorana, which explore the fundamental aspects of genetic translation.
Recommended video:
Guided course
08:39mRNA Processing
Related Practice
Textbook Question
Har Gobind Khorana and his colleagues performed numerous experiments translating synthetic mRNAs. In one experiment, an mRNA molecule with a repeating UG dinucleotide sequence was assembled and translated.
If the genetic code were overlapping rather than nonoverlapping, how would the result of this experiment be different?
4
views
Textbook Question
An experiment by Khorana and his colleagues translated a synthetic mRNA containing repeats of the trinucelotide UUG.
What is the result obtained from each reading frame?
Textbook Question
Har Gobind Khorana and his colleagues performed numerous experiments translating synthetic mRNAs. In one experiment, an mRNA molecule with a repeating UG dinucleotide sequence was assembled and translated.
If the genetic code were a doublet code instead of a triplet code, how would the result of this experiment be different?
Textbook Question
Har Gobind Khorana and his colleagues performed numerous experiments translating synthetic mRNAs. In one experiment, an mRNA molecule with a repeating UG dinucleotide sequence was assembled and translated.
How did the polypeptide composition help confirm the triplet nature of the genetic code?
3
views
Textbook Question
The human β-globin polypeptide contains 146 amino acids. How many mRNA nucleotides are required to encode this polypeptide?