Liberal Arts Blog — Missing Links III — DNA and RNA Machinery

John Muresianu
3 min readAug 19, 2020


Liberal Arts Blog — Wednesday is the Joy of Science, Engineering, and Technology Day

Today’s Topic — Missing Links III — DNA and RNA Machinery

Nothing is more mind-boggling than the whole DNA thing. I loved learning about the different kinds of DNA and RNA. But it was, well, kind of confusing. Where did those tRNA come from? How did they happen to have amino acids on one side and an anticodon on the other? Where did those amino acids come from anyway? This is the story of the amazing journey of those amino acids from that steak you just ate to the tRNA slaving away in the cytoplasm in each of your cells. Experts — please chime in. Correct, elaborate, elucidate.


1. First the proteins in that steak had to be denatured by digestive enzymes.

2. Then they had to be absorbed through the walls of the gut.

3. Then transported by the portal circulation to the liver and thence to vena cava into the pulmonary circulation, then pumped out via the left ventricle into the systemic circulation.


1. Then through the hepatic artery to the kidney.

2. Absorbed and reabsorbed in the glomerulus.

3. Then sent all over the body to every little cell where the most magic of enzymes (aminoacyl tRNA synthetase) does its thing.

AMINO ACYL tRNA SYNTHETASE (ARS) — think “supercalifragilisticexpialidocious”

1. Remember the song in Mary Poppins, “Supercalifragilisticexpialidocious”? Every kid loved saying the word.

2. Well, to me, the closest thing in all of science is tRNA aminoacyl synthetase.

3. The enzyme that “charges” the tRNA by adding the appropriate amino acid to one end while the appropriate anti-codon sits patiently waiting on the other.

NB: The charged tRNA then goes to the ribosome “assembly line” where the anti-codon is matched to the messenger RNA on one side and the amino acid to the protein chain on the other. (see first image above)

PS: How does the ARS know exactly what to do? How does it do it so fast? and so well? Getting beyond my pay grade here — really fast. Any help?

Aminoacyl tRNA synthetase

Transfer RNA



Please share the coolest thing you learned this week related to science, engineering, or technology. Or, even better, the coolest or most important thing you learned in your life related to science and engineering.

This is your chance to make someone else’s day. Or to cement in your mind something that you might otherwise forget. Or to think more deeply about something dear to your heart. Continuity is key to depth of thought.



John Muresianu

Passionate about education, thinking citizenship, art, and passing bits on of wisdom of a long lifetime.