17.3 RNA modification video

17.3-Modifying RNA notes

17.3-Modifying RNA

• Alteration
  • The 5’ end receives a modified nucleotide 5’ cap.
  • The 3’ end gets a poly-A tail
• Functions
  • They seem to facilitate the expert of mRNA to the cytoplasm
  • They protect mRNA from hydrolytic enzymes
  • They help ribosomes attach to the 5’ end
• Split genes and RNA splicing
  • Introns are noncoding regions
  • Exons are eventually expressed
  • RNA splicing removes introns and joins exons
  • RNS splicing is carried out by spliceosomes
  • Spliceosomes proteins several small nuclear ribonucleoproteins (snRNPs)
• Ribozymes
  • Catalytic RNA molecules that function as enzymes and can splice RNA
  • The discovery of ribosomes rendered obsolete the belief that all biological catalysts were proteins.
• 3D proteins of RNA enable it to function as an enzyme
  • Form a 3D structure, base pair with itself
  • Functional groups participate in catalysis
  • Hydrogen-bond with other nucleic acid molecules

Exon shuffling may result in the evolution of new proteins