CHAINS
by Arthur W. Siebens, Ph.D., Copyright 1995
(Chorus to the tune of "Chains," by Gerald Goffin and Carole King, as sung by the Beatles)

CHORUS
Chains -- biology is all full of chains
But they ain't the kind, that you can see
No, to see these chains takes electron microscopy.

Chains -- polymers are what we call chemical chains
Chains made of monomers -- chemical links
If your brain weren't made with polymers you couldn't think.

Starch -- starch is just a chemical chain
Chain made of glucose, a thousand links long
Repeat the same old bond (alpha-1,4 glycosidic linkage), never get it wrong.

Now plants store glucose as starch -- think they're cool
You eat the starch, digest it -- your small intestine ain't no fool.
Now you're back to glucose, you burn it (oxidize it) if you please
If not your liver stores it as glycogen, for your future needs
'Course glycogen's a chain ...CHORUS

Protein, protein's another chemical chain
Made of amino acids, a thousand links long
Repeat that peptide bond, never get it wrong.

Now when you eat protein from meat or baked beans
Your small intestine digests it to amino acids -- the building blocks you need
Then your muscle cells use them to make you strong like Arnold
So remember next time you flex, that bulge that makes your shirt rip is made of chains ...CHORUS

DNA and other nucleic acids are just giant chains
Chains of nucleotides, a thousand links long
Repeat the same old bond (phosphodiester linkage), never get it wrong.

Now like the others DNA's digested in your G.I. (gastrointestinal) tract, oh yeah
Then your cells can make what used to code for peanuts
Code for you, in fact.
With similar nucleotides you could also make RNA
Its flexible, there's no waste, your cells make what they need that day.
But they usually make chains ...CHORUS

Lipids, lipids are usually short kinds of chains
Chains of fatty acids, just three links long
Attached to glycerol (ester linkage), never get it wrong.

Now, distinguishing triglycerides don't take much toil, no, no
If it's a solid at room temp its a fat, if it's a liquid it's an oil
In any case lipids don't dissolve in H2O
'Course waxes and steroids are also lipids, but they're harder to know
'Cause they're not chains ...CHORUS
Yes, to see these chains takes electron microscopy!