Protein Synthesis

• If a DNA sequence is TAC TAG what is the mRNA sequence?

  • AUG AUC
• What's a difference in the step for translation in a eukaryotic organism compared to a prokaryotic?

  • Pre-mRNA has to be spliced to remove introns leaving room for exons, forming mRNA.
  • This then leaves via a nuclear pore and enters the cytoplasm.
• What is the role of RNA polymerase?

  • It joins mRNA nucleotides forming phosphodiester bonds between adjacent nucleotides in the backbone.
• What's a common error made in terms of the role of DNA/RNA polymerase and what bonds they form?

  • A common error is people saying that they form hydrogen bonds between bases which they DO NOT
• What's the difference between prokaryotes and eukaryotes in terms of splicing?

  • No splicing occurs in prokaryotes as their DNA does not contain introns.
  • Compared to eukaryotes where splicing occurs as they contain introns.
• What is the role of tRNA in translation?

  • It carries a specific amino acid to ribosomes, the anticodon is complementary to the codon resulting in the correct sequence of amino acids along a polypeptide
• What is the role of ATP in translation?

  • It assists in the binding of tRNA to a specific amino acid and the formation of a peptide bond between amino acids
• What is the role of ribosomes in translation?

  • mRNA binds to ribosomes with two codons allowing tRNA with anticodons to bind.
  • It catalyses the formation of peptide bonds between amino acids then moves along mRNA to the next codon.