Transcription

• What is transcription?

  synthesis of RNA from DNA
• Where is transcription?

  in the nucleus
• Nuclear pore?

  holes in the nucleus that mRNA leaves through
• Can DNA go through the nuclear pores?

  No
• How much DNA is transcripted at once?

  A single gene
• role of DNA helicase?

  Breaks the H bonds and unwinds DNA strands
• role of DNA polymerase?

  Brings new nucleotides and form phosphodiester bonds to make the SP backbones
• Where is pre- mRNA found?

  In eukaryotes
• Is pre- mRNA in eukaryotes and prokaryotes?

  No just eukaryotes
• Introns ?

  non coding sections
• Exons?

  Coding sections
• Genome?

  Complete set of genes
• Proteome?

  Full range of proteins that can be made from the genome
• When does transcription start

  at a start codon when the DNA unwinds
• When does transcription finish?

  At a stop codon
• Structure and function of mRNA?

  Comp to DNA and tRNA

  variable, codes for different proteins

  Relatively small

  Unstable
• Why is mRNA small?

  To fit out the nuclear pores
• Why is mRNA unstable?

  So it controls protein production, if it isn’t happening quick enough it breaks back down into amino acids
• How is mRNA formed by transcription in eukaryotes?

  H bonds breaks

  1 DNA strand acts as a template

  RNA nucleotides align with comp base

  Phosphodiester bonds between nucleotides

  Pre - mRNA is spliced to form mRNA
• Spicing meaning?

  Removing intron sections and putting exon sections together
• transcription process

  DNA unwinds and H bonds break

  one strand acts as a template

  free RNA nucleotides align by comp pairing

  H bonds form

  RNA polymerase joins and forms phosphodiester bonds between nucleotides

  intron sections removed

  mRNA leaves the nuclear pore