The Central Dogma

As you have learned, information flow in an organism takes place from DNA to RNA to protein:

  • DNA is transcribed to RNA via complementary base pairing rules (but with U instead of T in the transcript)
  • The RNA transcript, specifically mRNA, is then translated to an amino acid polypeptide
  • Final folding and modifications of the polypeptide lead to functional proteins that actually do things in cells

This is known as the Central Dogma of Life, which holds true for all organisms.

To make a protein, genetic information encoded by the DNA must be transcribed onto an mRNA molecule. The RNA is then processed by splicing to remove exons and by the addition of a 5′ cap and a poly-A tail. A ribosome then reads the sequence on the mRNA, and uses this information to string amino acids into a protein.

Figure 1. Click for a larger image. Instructions on DNA are transcribed onto messenger RNA. Ribosomes are able to read the genetic information inscribed on a strand of messenger RNA and use this information to string amino acids together into a protein.

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