Protein Synthesis: How DNA Results in Traits

Introduction to Protein Synthesis

• DNA contains genetic information for traits, such as eye color.
• Traits result from pigments, which are made via proteins coded by genes.
• Protein Synthesis: Process by which DNA leads to protein formation; essential for life.
• Proteins play crucial roles in:
  • Transport
  • Structure
  • Enzyme activity
  • Body protection

DNA and RNA in Protein Synthesis

• DNA located in cell nucleus; some is noncoding or inactive.
• Role of RNA: Vital for protein synthesis.
  • RNA is a nucleic acid similar to DNA but with differences.

Steps of Protein Synthesis

1. Transcription

• Occurs in the nucleus.
• Process:
  • RNA polymerase connects complementary RNA bases to DNA.
  • Forms single-stranded mRNA (messenger RNA).
  • mRNA undergoes editing before leaving the nucleus.
• mRNA exits nucleus to cytoplasm and attaches to ribosome.

2. Translation

• Takes place in the cytoplasm.
• Ribosome: Composed of rRNA (ribosomal RNA); facilitates protein assembly.
• tRNA (transfer RNA): Brings amino acids to ribosome.
  • Amino acids are protein building blocks.
  • tRNA matches with mRNA codons to transfer amino acids.

Detailed Mechanism of Translation

• Codons: mRNA bases read in triplets (e.g., AUG).
  • tRNA has complementary anticodon (e.g., UAC) carrying specific amino acid (e.g., methionine).
  • Use of codon chart to identify amino acids for mRNA codons.
• Peptide Bonds: Connect amino acids into a chain.
  • Process continues until a stop codon is reached, concluding protein synthesis.

Conclusion

• Outcome: Chain of amino acids formed, directed by DNA via mRNA, rRNA, and tRNA.
• Protein folding, modification, and transport may follow based on function.
• Encouragement to explore further into detailed processes.