Protein Synthesis Notes

Overview of Protein Synthesis

• Protein synthesis is the process by which proteins are created in the cell, involving two main stages: transcription and translation.

Key Steps in Protein Synthesis

• Step 1: DNA Replication

  • The DNA strand must first be used to create a complementary strand.
  • Base Pairing Rules for DNA:
  • Adenine (A) pairs with Thymine (T)
  • Guanine (G) pairs with Cytosine (C)

• Step 2: Transcription

  • During transcription, the DNA sequence is used to produce messenger RNA (mRNA).
  • Base Pairing Rules for mRNA:
  • Adenine (A) pairs with Uracil (U)
  • Guanine (G) pairs with Cytosine (C)

• Step 3: Translation

  • mRNA is read by the ribosome to synthesize proteins.
  • The mRNA is divided into codons, each codon consists of three bases that code for a specific amino acid.

Codon Table

• Familiarize yourself with the Codon Table used for translation:

mRNA and tRNA

• mRNA:
  • Carries the genetic code from the DNA to the ribosome for protein synthesis.
  • Has codons (sets of three nucleotides).
• tRNA:
  • Transfers the appropriate amino acids to the ribosome, matching them to the mRNA codons.
  • Has anti-codons (complementary to mRNA codons).

Key Questions to Remember

1. mRNA is synthesized during transcription.
2. mRNA contains codons, while tRNA carries anti-codons.

Example Codon to Amino Acid Translation

• If the mRNA sequence is AUG CCU GAC, the translation would follow:
  • mRNA Codons: AUG -> Methionine, CCU -> Proline, GAC -> Aspartic acid
  • tRNA Anti-codons: UAC, GGA, CUG