The Central Dogma

What you’ll learn to do: Identify the central dogma of life

As you have learned, information flow in an organism takes place from DNA to RNA to protein. DNA dictates the structure of mRNA in a process known as transcription, and RNA dictates the structure of protein in a process known as translation. This is known as the Central Dogma of Life.

Does the Central Dogma always apply?

Scientists are always experimenting and exploring within their current understanding of the world. As they learn and discover new things, their ideas and understanding change to reflect the new evidence they have before them.

With modern research, it is becoming clear that some aspects of the central dogma are not entirely accurate. In order to flesh out our understanding, current research is focusing on investigating the function of non-coding RNA. Although this molecules does not follow the central dogma it still has a functional role in the cell.

Learning Outcomes

Identify the central dogma of life

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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Check Your Understanding

Answer the question(s) below to see how well you understand the topics covered in the previous section. This short quiz does not count toward your grade in the class, and you can retake it an unlimited number of times.

Use this quiz to check your understanding and decide whether to (1) study the previous section further or (2) move on to the next section.