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Protein synthesis and DNA replication 

Transcription:

  • DNA is ‘unzipped’ by DNA helicase and this breaks the hydrogen bonds between the complementary bases

  • Free nucleotides line up along the anti-sense strand

  • RNA polymerase catalyses the phosphodiester bonds being formed between adjacent nucleotides

  • The mRNA moves out of the nucleus from the nuclear pore into the cytoplasm

    RNA vs DNA:

  • RNA is smaller and DNA is larger

  • RNA has uracil instead of thymine in DNA

  • RNA is single stranded and DNA is double stranded

    Transcription vs replication

  • Replication uses both strands and transcription only uses one strand

  • Replication forms DNA and transcription forms mRNA

  • Replication uses DNA polymerase and transcription uses RNA polymerase

  • Replications’ product stays in the nucleus and transcriptions product leaves the nucleus

    Translation****:

  • The ribosome attaches itself onto the mRNA strand

  • Ribosome slides along until the start codon (AUG) is reached

  • A tRNA molecule binds to the mRNA via its anti-codon and forms hydrogen bonds - the tRNA molecule is attached to a specific amino acid

  • The next tRNA molecule brings another amino acid and binds to the next codon - the amino acids form peptide bonds in between them

  • This process repeats until the stop codon or release factor is reached on the mRNA

    DNA replication

  • DNA is ‘unzipped’ by DNA helicase

  • The hydrogen bonds are broken between the bases

  • The strands act as templates to the new strand

  • The exposed bases attract complementary bases

  • They form new hydrogen bonds between them And adjacent nucleotides are joined by phosphodiester bonds formed in condensation reactions

  • DNA polymerase and DNA ligase form the sugar-phosphate backbone

  • 2 identical DNA strands are formed

  • This happens semi-conservitavly (one strand is old, one strand is new)

Protein synthesis and DNA replication 

Transcription:

  • DNA is ‘unzipped’ by DNA helicase and this breaks the hydrogen bonds between the complementary bases

  • Free nucleotides line up along the anti-sense strand

  • RNA polymerase catalyses the phosphodiester bonds being formed between adjacent nucleotides

  • The mRNA moves out of the nucleus from the nuclear pore into the cytoplasm

    RNA vs DNA:

  • RNA is smaller and DNA is larger

  • RNA has uracil instead of thymine in DNA

  • RNA is single stranded and DNA is double stranded

    Transcription vs replication

  • Replication uses both strands and transcription only uses one strand

  • Replication forms DNA and transcription forms mRNA

  • Replication uses DNA polymerase and transcription uses RNA polymerase

  • Replications’ product stays in the nucleus and transcriptions product leaves the nucleus

    Translation****:

  • The ribosome attaches itself onto the mRNA strand

  • Ribosome slides along until the start codon (AUG) is reached

  • A tRNA molecule binds to the mRNA via its anti-codon and forms hydrogen bonds - the tRNA molecule is attached to a specific amino acid

  • The next tRNA molecule brings another amino acid and binds to the next codon - the amino acids form peptide bonds in between them

  • This process repeats until the stop codon or release factor is reached on the mRNA

    DNA replication

  • DNA is ‘unzipped’ by DNA helicase

  • The hydrogen bonds are broken between the bases

  • The strands act as templates to the new strand

  • The exposed bases attract complementary bases

  • They form new hydrogen bonds between them And adjacent nucleotides are joined by phosphodiester bonds formed in condensation reactions

  • DNA polymerase and DNA ligase form the sugar-phosphate backbone

  • 2 identical DNA strands are formed

  • This happens semi-conservitavly (one strand is old, one strand is new)

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