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
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