Reading a Codon Chart and Identifying Amino Acids

Introduction

• Essential for genetics, molecular biology, and related fields.
• Codon charts help understand the genetic code by translating DNA/RNA sequences into proteins.
• Each codon corresponds to an amino acid or a signal in protein synthesis.

The Genetic Code and Codons

• Genetic Code: Set of rules to translate DNA/RNA into proteins.
• Universal across all organisms.
• Codons: Sequences of three nucleotides (U, C, A, G).
• Example of mRNA sequence: AUG-GGU-CAA-UAA.
• 64 possible codons due to four nucleotides.

What Is a Codon Chart?

• Visual representation mapping codons to amino acids/signals.
• Two types: square/rectangle and circular forms.
• Decodes mRNA sequences into amino acids.

Reading a Codon Chart

• Start with the first nucleotide (left), second (top), third (right) to identify the amino acid.

Specific Codons and Amino Acids

• Asparagine (Asn): AAU, AAC
• Glutamine (Gln): CAA, CAG
• Glycine (Gly): GGU, GGC, GGA, GGG
• Methionine (Met): AUG
• Phenylalanine (Phe): UUU, UUC
• Proline (Pro): CCU, CCC, CCA, CCG
• Valine (Val): GUU, GUC, GUA, GUG

Redundancy in Genetic Code

• Multiple codons can encode the same amino acid (e.g., Ala: GCU, GCC, GCA, GCG).
• Provides a safeguard against mutations.

How to Use a Codon Chart

1. Identify mRNA Sequence: Transcribe from DNA.
2. Locate Start Codon: AUG for methionine.
3. Translate Codons: Use the chart to find amino acids.
4. End at Stop Codon: UAA, UAG, or UGA.

Origins of the Codon Table

• Developed from mid-20th century research.
• Watson and Crick's DNA structure discovery in 1953.
• Nirenberg and Matthaei's experiments in the 1960s.
• First codon deciphered was UUU for phenylalanine.
• Further research by Khorana and others led to full deciphering by 1966.

Significance in Biology and Medicine

• Biology: Enables gene expression studies, gene modification, and protein production.
• Medicine: Advances genetic research, therapeutic interventions, gene therapy, and vaccine development.
• Examples: Production of insulin, growth hormones, mRNA vaccines (e.g., COVID-19 vaccines).

Article created in conjunction with AI technology and fact-checked by HowStuffWorks.