Translation

• • mRNA leaves the nucleus, moves into the cytoplasm and attaches to the ribosome. -Sequence of mRNA codons determines sequence of amino acids
  • tRNAs carry specific amino acids, in relation to their anticodon
  • At the ribosome, tRNA codon binds to mRNA codon - trna complementary to mrna codon form hydrogen bonds
  • First codon = startcodon
  • Two amino acids joined by condensation, forming a peptide bond
  • Using energy from АТР

  tRNA detaches (without its amino acid), ribosome moves along mRNA to next codon

  • Continues until stop codon (polypeptide released)

  
• What is role of ATP in translation?

  Energy source

  hydrolysis ATP to ADP + Pi- releases energy for

  1. bond between amino acids and tRNA molecule ( amino acid binding site)

  2. peptide bond formation between amino acids
• what is role of tRNA in translation?

  tRNA attaches to and transports a specific amino acid, in relation to its anticodon

  • tRNA anticodon complementary base pairs to mRNA codon, forming hydrogen bonds
  • Two tRNAs bring amino acids together for the formation of a peptide bonds
  • About 60 types of tRNAs to carry 20 different amino acids

  Genetic code is degenerate
• Role of ribosomes in translation?

  • Attaches to mRNA and houses tRNA, allowing codon-anticodon complementary base pairing

  Allows peptide bonds to form between amino acids
• • tRNA anticodons are complementary to mRNA codon template strand
  • E.g. mRNA codon = ACG; tRNA anticodon = UGC
  • mRNA sequence of bases / codons are complementary to sequence of bases / triplets on DNA
  • E.g. mRNA base sequence = ACG UAG AAC; DNA base sequence = TGC ATC TTG
  • In RNA, uracil replaces thymine
  • You may then have to relate this to amino acid sequences