L9. RNA

• What is the function of single-strand binding protein?

  Stabilise single stranded DNA until template
• Which statement is true about purines?

  Adenine and guanine are purines
• What observation did Hershey and Chase use in their experiments?

  DNA contains phosphate and protein contains sulphur
• How are complementary strands of DNA held together?

  Weak hydrogen bonds
• Why can't both new strands of DNA be replicated continuously?

  Chains extend in one direction only 5’ - 3’
• What is the error rate in DNA replication for Escherichia coli?

  • About 1 in 10$^9$ base pairs
  • Rapid and accurate process
  • Achieved by specific base-pairing and proofreading
• How much DNA is there in a human cell?

  About 1 metre of DNA per cell
• What is mitochondrial DNA (mtDNA) like?

  Double stranded and circular, like bacterial DNA
• How is mtDNA inherited?

  Passed via maternal lineage, no mixing
• What do mutations in mtDNA cause?

  Over 40 different diseases
• What are the learning objectives for Lecture 13 on RNA?

  • Evidence for the link between genes and proteins
  • Copying action of RNA polymerases
  • Role of DNA template during transcription
  • Processing of RNA transcripts in eukaryotic cells
• Who suggested the link between genes and proteins?

  Garrod in 1909
• What did Beadle and Tatum study?

  Link between genes and protein synthesis
• What is the "one gene-one enzyme" hypothesis?

  Each gene regulates a specific enzyme
• What are the three stages of transcription?

  1. Initiation
  2. Elongation
  3. Termination
• What is the role of mRNA in protein synthesis?

  mRNA is the intermediate between DNA and proteins
• What is the process of transcription?

  Copying genetic information from DNA to mRNA
• What is mRNA splicing?

  Removal of non-coding sequences from pre-mRNA
• What marks the splice sites in mRNA splicing?

  Short nucleotide sequences at end of introns
• What comes first: translation, transcription, or RNA processing?

  Transcription
• What is the role of RNA polymerase?

  It synthesizes RNA from the DNA template
• Which statement is true about RNA transcripts?

  The RNA transcript is extensively modified before leaving the nucleus
• What is the orange piece of RNA in the diagram known as?

  An Intron
• What should you familiarize yourself with from Lecture 9?

  • Work of Garrod on inborn errors of metabolism
  • Beadle/Tatum's one gene, one enzyme concept
  • Three stages of transcription
  • RNA processing in eukaryotic cells