Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

11. Translation

The Genetic Code

Genetics

11. Translation

The Genetic Code

Previous problemNext problem

1:13 minutes

Problem 1c

Textbook Question

How were the specific sequences of triplet codes determined experimentally?

Verified step by step guidance

Step 1: Understand the concept of the genetic code. The genetic code consists of triplet codons, where each codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid or a stop signal during translation.

Step 2: Learn about the experimental methods used to determine the triplet codes. One key method was the use of synthetic RNA molecules in cell-free translation systems. Researchers synthesized RNA sequences with known nucleotide compositions and observed the resulting polypeptides.

Step 3: Explore the work of Marshall Nirenberg and Heinrich Matthaei. They conducted experiments using poly(U) RNA (a sequence of uracil nucleotides) in a cell-free system, which led to the discovery that the codon UUU codes for the amino acid phenylalanine.

Step 4: Investigate the use of mixed RNA sequences. Researchers created RNA molecules with repeating patterns (e.g., poly(UC)) and analyzed the resulting polypeptides to deduce the codons for specific amino acids.

Step 5: Examine the use of triplet binding assays. In this method, researchers used ribosomes, tRNA, and synthetic triplet codons to determine which amino acid-tRNA pairs bind to specific codons, further confirming the genetic code.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

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 information encoded in DNA is translated into proteins. It consists of triplet codons, each made up of three nucleotides, which correspond to specific amino acids. Understanding the genetic code is essential for deciphering how sequences of DNA dictate the structure and function of proteins.

Transcription

Transcription is the process by which the genetic information in DNA is copied into messenger RNA (mRNA). This process involves the enzyme RNA polymerase, which binds to the DNA and synthesizes a complementary RNA strand. Transcription is a critical step in gene expression, as it allows the information in DNA to be translated into functional proteins.

Experimental Determination of Codons

The specific sequences of triplet codes were determined through various experimental methods, including the use of synthetic RNA and ribosomes. Researchers like Marshall Nirenberg and Har Gobind Khorana conducted experiments that involved creating artificial mRNA sequences and observing the resulting protein synthesis, which helped to identify which codons corresponded to which amino acids.

Watch next

Master The Genetic Code with a bite sized video explanation from Kylia

Start learning

Related Videos

Related Practice

Multiple Choice

Which of the following characteristics does NOT describe the triplet codon code?

Which of the following codons is a start codon?

Which of the following were used to discover the triplet code?

How were the experimentally derived triplet codon assignments verified in studies using bacteriophage MS2?

401

views

Textbook Question

What experimental evidence provided the initial insights into the compositions of codons encoding specific amino acids?

541

views

Textbook Question

Why did geneticists believe, even before direct experimental evidence was obtained, that the genetic code would turn out to be composed of triplet sequences and be nonoverlapping? Experimentally, how were these suppositions shown to be correct?

427

views

Textbook Question

In the experiments that deciphered the genetic code, many different synthetic mRNA sequences were tested.

Predict the results of experiments examining GCUA repeats.

501

views

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...?

478

views