What is a zwitter ion,general structure
Answers
What is a Zwitterion?
Let's take the word zwitterion apart to figure out what it means. There's the -ion part at the end, which is a chemical species with a charge. The first part of the name comes from the German word 'zwitter', meaning hermaphrodite or hybrid. In other words, this term means half anion and half cation. Zwitterions are sometimes called dipolar ions, because they have a negative end (the anion) and a positive end (the cation).
Amino Acids as Zwitterions
Amino acids are the building blocks of proteins in living cells. They are compounds that contain an amino group and a carboxyl group. Twenty different amino acids are found in proteins. They share the structure shown here, where R represents one of the 20 possible side chains on an amino acid.
General structure of an amino acid
amino_acid_structure
At neutral pH values, the amino group (-NH3+) has a positive charge and the carboxyl group (COO-) has a negative charge. Here is what the simplest amino acid, glycine, looks like in its zwitterion form:
Zwitterion form of glycine
glycine
The other interesting thing about zwitterions is if there are no other charged groups in the molecule, then a zwitterion has no net charge. That's right - a positive charge (+1) and a negative charge (-1) add up to zero.
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